Showing 1–50 of 520 results for author: Jiang, J

Gate-imprinted memory and light-induced erasure of superconductivity at KTaO_3-based interfaces

Authors: Zhihao Chen, Pengxu Ran, Jiexiong Sun, Fengmiao Li, Zhixin Yao, Lei Liu, Juan Jiang, Zhi Gang Cheng

Abstract: Realizing non-volatile control of superconductivity is a key step toward integrating memory and quantum functionality in future information technologies. KTaO_3-based heterostructures uniquely host both interfacial two-dimensional superconductivity and a quantum paraelectric lattice background. The coupling between these two degrees of freedom potentially provides a promising route to encode memor… ▽ More Realizing non-volatile control of superconductivity is a key step toward integrating memory and quantum functionality in future information technologies. KTaO_3-based heterostructures uniquely host both interfacial two-dimensional superconductivity and a quantum paraelectric lattice background. The coupling between these two degrees of freedom potentially provides a promising route to encode memory directly into the superconducting state. Here, we reveal two intertwined phenomena in AlO_x/KTaO_3 heterostructures: a gate-history memory in which progressive electrostatic cycling enhances the superconducting transition temperature, and its complete erasure by light illumination at cryogenic temperatures. These phenomena arise from a previously unrecognized interplay between the superconducting interface and emergent lattice excitations - including polar-nanoregion reorientation and oxygen-vacancy ionization. These results demonstrate reconfigurable and non-volatile superconductivity at correlated oxide interfaces, opening a pathway to combine dissipationless transport with non-volatility for superconducting neuromorphic elements. △ Less

Submitted 22 December, 2025; originally announced December 2025.

Topological surface phonons modulate thermal transport in semiconductor thin films

Authors: Zhe Su, Shuoran Song, Qi Wang, Jian-Hua Jiang

Abstract: While phonon topology in crystalline solids has been extensively studied, its influence on thermal transport-especially in nanostructures-remains elusive. Here, by combining first-principles-based machine learning potentials with the phonon Boltzmann transport equation and molecular dynamics simulations, we systematically investigate the role of topological surface phonons in the in-plane thermal… ▽ More While phonon topology in crystalline solids has been extensively studied, its influence on thermal transport-especially in nanostructures-remains elusive. Here, by combining first-principles-based machine learning potentials with the phonon Boltzmann transport equation and molecular dynamics simulations, we systematically investigate the role of topological surface phonons in the in-plane thermal transport of semiconductor thin films (Si, 4H -SiC, and c-BN). These topological surface phonons, originating from nontrivial acoustic phonon nodal lines, not only serve as key scattering channels for dominant acoustic phonons but also contribute substantially to the overall thermal conductivity. Remarkably, for these thin semiconductor films below 10 nm this contribution can be as large as over 30% of the in-plane thermal conductivity at 300 K, and the largest absolute contribution can reach 82 W/m-K, highlighting their significant role in nanoscale thermal transport in semiconductors. Furthermore, we demonstrate that both temperature and biaxial strain provide effective means to modulate this contribution. Our work establishes a direct link between topological surface phonons and nanoscale thermal transport, offering the first quantitative assessment of their role and paving the way for topology-enabled thermal management in semiconductors. △ Less

Submitted 21 December, 2025; originally announced December 2025.

Fresnel Magnetic Imaging of Ultrasmall Skyrmion Lattices

Authors: Yongsen Zhang, Wei Liu, Meng Shi, Yaodong Wu, Jialiang Jiang, Sheng Qiu, Huanhuan Zhang, Hui Han, Mingliang Tian, Haifeng Du, Shouguo Wang, Jin Tang

Abstract: Magnetic skyrmions with ultrasmall nanometric dimensions hold significant promise for next-generation high-density spintronic devices. Direct real-space imaging of these topological spin textures is critical for elucidating their emergent properties at the nanoscale. Here, we present Lorentz transmission electron microscopy studies of nanometric skyrmion lattices in B20-structured Mn0.5Fe0.5Ge cry… ▽ More Magnetic skyrmions with ultrasmall nanometric dimensions hold significant promise for next-generation high-density spintronic devices. Direct real-space imaging of these topological spin textures is critical for elucidating their emergent properties at the nanoscale. Here, we present Lorentz transmission electron microscopy studies of nanometric skyrmion lattices in B20-structured Mn0.5Fe0.5Ge crystals using Fresnel mode. According to conventional chiral discrimination methods relying on static bright-dark contrast, we demonstrate an abnormal periodic chiral-reversal phenomenon retrieved through the transport of intensity equation analysis of defocus-dependent Fresnel images. Through systematic off-axis electron holography experiments and numerical simulations, we attribute these chiral misinterpretations to the sinusoidal modulation mechanism of the contrast transfer functionthat correlates with both defocus values and skyrmion dimensions. Our findings establish quantitative limitations of conventional Fresnel contrast analysis for ultrasmall skyrmions while revealing fundamental insights into defocus-mediated phase-to-intensity conversion processes in nanoscale magnetic imaging. △ Less

Submitted 11 December, 2025; originally announced December 2025.

Comments: Published in Advanced Science

Investigating the origin of topological-Hall-like resistivity in Zn-doped Mn2Sb ferrimagnet

Authors: BoCheng Yu, JiaLiang Jiang, Jing Meng, XiaoYan Zhu, Jie Ma, HaiFeng Du, QingFeng Zhan, Jin Tang, Yang Xu, Tian Shang

Abstract: Skyrmions and other chiral spin textures have been extensively studied as potential building blocks for novel spintronic devices. Hall-resistivity anomalies that deviate from magnetization scaling, known as the topological Hall effect, have been widely employed as evidence for the presence of chiral spin textures in magnetic materials. However, recent studies on magnetic thin films have revealed a… ▽ More Skyrmions and other chiral spin textures have been extensively studied as potential building blocks for novel spintronic devices. Hall-resistivity anomalies that deviate from magnetization scaling, known as the topological Hall effect, have been widely employed as evidence for the presence of chiral spin textures in magnetic materials. However, recent studies on magnetic thin films have revealed a drawback of this approach, as the presumed topological Hall contribution may in fact originate from trivial mechanisms. Here, we investigate the magnetic and transport properties of a Zn-doped Mn2Sb ferrimagnet, whose related compounds have previously been suggested to exhibit a topological Hall effect arising from chiral spin textures. Hall-resistivity anomalies are also observed in our sample, yet they show little correlation with the magnetic or metamagnetic transitions and are therefore clearly distinct from those in magnetic compounds hosting chiral spin textures. Most importantly, additional Lorentz transmission electron microscopy measurements rule out the existence of chiral spin textures in this ferrimagnet. Therefore, instead of a nontrivial origin, we attribute the Hall-resistivity anomalies to the combined effect of multiple anomalous Hall channels resulting from sample inhomogeneity. Our work shows that the difficulties of identifying chiral spin textures through transport measurements also apply to bulk systems, prompting some existing results to be revisited. △ Less

Submitted 11 December, 2025; originally announced December 2025.

Comments: 15 figures, 49 pages; accepted by Rare Metals

Deterministic Electrical Control of Single Magnetic Bubbles in Nanostructured Cells

Authors: Jialiang Jiang, Yaodong Wu, Lingyao Kong, Yongsen Zhang, Sheng Qiu, Huanhuan Zhang, Yihao Wang, Junbo Li, Yimin Xiong, Shouguo Wang, Mingliang Tian, Haifeng Du, Jin Tang

Abstract: Localized particle-like spin textures have been found to exhibit emergent electromagnetic properties, which hold promise for the development of intriguing spintronic devices. Among these textures, magnetic bubbles represent localized spin configurations that could serve as data bits. However, the precise methods for their electrical manipulation remain uncertain. Here, we demonstrate the determini… ▽ More Localized particle-like spin textures have been found to exhibit emergent electromagnetic properties, which hold promise for the development of intriguing spintronic devices. Among these textures, magnetic bubbles represent localized spin configurations that could serve as data bits. However, the precise methods for their electrical manipulation remain uncertain. Here, we demonstrate the deterministic electrical manipulations and detections of single magnetic bubbles in kagome-latticed Fe3Sn2 magnetic nanostructured cells. The current-induced dynamics of magnetic bubbles were explored using nanosecond pulsed currents. We show single pulsed currents with low and high densities can be applied for the creation and deletion of a single bubble, respectively. The mutual writing-deleting operations on single bubbles are attributed to the thermal heating and non-thermal spin-transfer torque effects in combination with micromagnetic simulations. We also realized the in-situ detection of a single bubble using the anisotropic magnetoresistance effect through a standard four-probe method. Our results could propel the development of bubble-based spintronic devices. △ Less

Submitted 10 December, 2025; originally announced December 2025.

Comments: Published in Advanced Functional Materials

Creating and Deleting a Single Dipolar Skyrmion by Surface Spin Twists

Authors: Jin Tang, Jialiang Jiang, Yaodong Wu, Lingyao Kong, Yihao Wang, Junbo Li, Y. Soh, Yimin Xiong, Shouguo Wang, Mingliang Tian, Haifeng Du

Abstract: We report deterministic operations on single dipolar skyrmions confined in nanostructured cuboids using in-plane currents. We achieve highly reversible writing and deleting of skyrmions in the simple cuboid without any artificial defects or pinning sites. The current-induced creation of skyrmions is well-understood through the spin-transfer torque acting on surface spin twists of the spontaneous 3… ▽ More We report deterministic operations on single dipolar skyrmions confined in nanostructured cuboids using in-plane currents. We achieve highly reversible writing and deleting of skyrmions in the simple cuboid without any artificial defects or pinning sites. The current-induced creation of skyrmions is well-understood through the spin-transfer torque acting on surface spin twists of the spontaneous 3D ferromagnetic state, caused by the magnetic dipole-dipole interaction of the uniaxial Fe3Sn2 magnet with a low-quality factor. Current-induced deletions of skyrmions result from the combined effects of magnetic hysteresis and Joule thermal heating. Our results are replicated consistently through 3D micromagnetic simulations. Our approach offers a viable method for achieving reliable single-bit operations in skyrmionic devices for applications such as random-access memories. △ Less

Submitted 9 December, 2025; originally announced December 2025.

Comments: Published in Nano Letters

Current-controlled creations, deletions, and topological transformations of a single magnetic antiskyrmion in nanostructured cells

Authors: Yaodong Wu, Jialiang Jiang, Lingyao Kong, Wei Liu, Huanhuan Zhang, Shouguo Wang, Mingliang Tian, Haifeng Du, Jin Tang

Abstract: Topological magnetic solitons have emerged as promising candidates for information carriers in spintronic devices, thanks to their fascinating electromagnetic properties. For fundamental device applications, the ability to electrically manipulate individual solitons is crucial. However, electrical manipulation of single antiskyrmions has been rarely demonstrated. In this work, we present current-c… ▽ More Topological magnetic solitons have emerged as promising candidates for information carriers in spintronic devices, thanks to their fascinating electromagnetic properties. For fundamental device applications, the ability to electrically manipulate individual solitons is crucial. However, electrical manipulation of single antiskyrmions has been rarely demonstrated. In this work, we present current-controlled manipulations, encompassing the creation, deletion, and topological transformation of a single antiskyrmion within FeNiPdP nanostructured cells at room temperature. This nanostructure is uniquely designed with dimensions of about 400 nm in width and length, enabling the stabilization of a single antiskyrmion. By simply adjusting the density of nanosecond single-pulsed currents, we achieve the reversible creation and deletion of single antiskyrmions. Moreover, we uncover a rich variety of current-controlled topological transformations among individual antiskyrmions, skyrmions, bubbles, and ferromagnetic states. Our experimental findings are corroborated by micromagnetic simulations, highlighting the pivotal role of current-induced combined effects, such as spin transfer torque and Joule heating. Our results hold potential for advancing antiskyrmion-based device applications. △ Less

Submitted 9 December, 2025; originally announced December 2025.

Comments: Published in Nature Communications

Skyrmion Sliding Switch in a 90-nm-Wide Nanostructured Chiral Magnet

Authors: Yaodong Wu, Jialiang Jiang, Weiwei Wang, Lingyao Kong, Shouguo Wang, Mingliang Tian, Haifeng Du, Jin Tang

Abstract: Magnetic skyrmions, renowned for their fascinating electromagnetic properties, hold potential for next-generation topological spintronic devices. Recent advancements have unveiled a rich tapestry of 3D topological magnetism. Nevertheless, the practical application of 3D topological magnetism in the development of topological spintronic devices remains a challenge. Here, we showcase the experimenta… ▽ More Magnetic skyrmions, renowned for their fascinating electromagnetic properties, hold potential for next-generation topological spintronic devices. Recent advancements have unveiled a rich tapestry of 3D topological magnetism. Nevertheless, the practical application of 3D topological magnetism in the development of topological spintronic devices remains a challenge. Here, we showcase the experimental utilization of 3D topological magnetism through the exploitation of skyrmion-edge attractive interactions in 90-nm-wide confined chiral FeGe and CoZnMn magnetic nanostructures. These attractive interactions result in two degenerate equilibrium positions, which can be naturally interpreted as binary bits for a skyrmion sliding switch. Our theory and simulation reveal current-driven spiral motions of skyrmions, governed by the anisotropic gradient of the potential landscape. Our experiments validate the theory that predicts a tunable threshold current density via magnetic field and temperature modulation of the energy barrier. Our results offer an approach for implementing universal on-off switch functions in 3D topological spintronic devices. △ Less

Submitted 9 December, 2025; originally announced December 2025.

Comments: Published in Nano Letters

Accelerating discovery of infrared nonlinear optical materials with large shift current via high-throughput screening

Authors: Aiqin Yang, Dian Jin, Mingkang Liu, Daye Zheng, Qi Wang, Qiangqiang Gu, Jian-Hua Jiang

Abstract: Discovering nonlinear optical (NLO) materials with strong shift current response, particularly in the infrared (IR) regime, is essential for next-generation optoelectronics yet remains highly challenging in both experiments and theory, which still largely relies on case by case studies. Here, we employ a high-throughput screening strategy, applying a multi-step filter to the Materials Project data… ▽ More Discovering nonlinear optical (NLO) materials with strong shift current response, particularly in the infrared (IR) regime, is essential for next-generation optoelectronics yet remains highly challenging in both experiments and theory, which still largely relies on case by case studies. Here, we employ a high-throughput screening strategy, applying a multi-step filter to the Materials Project database (>154,000 materials), which yielded 2,519 candidate materials for detailed first-principle evaluation. From these calculations, we identify 32 NLO materials with strong shift current response ($σ$ > 100 $μA/V^2$). Our work reveals that layered structures with $C_{3v}$ symmetry and heavy $p$-block elements (e.g. Te, Sb) exhibit apparent superiority in enhancing shift current. More importantly, 9 of these compounds show shift current response peaks in the IR region, with the strongest reaching 616 $μA/V^2$, holding significant application potential in fields such as IR photodetection, sensing, and energy harvesting. Beyond identifying promising candidates, this work establishes a comprehensive and high-quality first-principles dataset for NLO response, providing a solid foundation for future AI-driven screening and accelerated discovery of high-performance NLO materials, as demonstrated by a prototype machine-learning application. △ Less

Submitted 4 December, 2025; originally announced December 2025.

Tetragonal Fe2O: the stable iron oxide at Earth's core conditions

Authors: Junjie Jiang, Zhen Zhang, Tongqi Wen, Renata M. Wentzcovitch, Yang Sun

Abstract: The Fe-O system is fundamental to understanding the composition and properties of the Earth's core. Recent studies have suggested the possible existence of stable, iron-rich FenO compounds at around 215 GPa. Here, we performed crystal-structure searches and fully anharmonic free-energy calculations to investigate the Fe-FeO system under inner-core conditions. We identified Fe2O as a stable phase a… ▽ More The Fe-O system is fundamental to understanding the composition and properties of the Earth's core. Recent studies have suggested the possible existence of stable, iron-rich FenO compounds at around 215 GPa. Here, we performed crystal-structure searches and fully anharmonic free-energy calculations to investigate the Fe-FeO system under inner-core conditions. We identified Fe2O as a stable phase and constructed its high P-T phase diagram. Fe2O undergoes a hexagonal-to-tetragonal transition with increasing pressure and temperature. It remains thermodynamically stable against decomposition into Fe and FeO from 200 to 400 GPa and at high temperatures. Although oxygen has been considered nearly absent in the inner core due to its limited solubility, these results suggest that oxygen can, in fact, be incorporated into the solid inner core in the form of an Fe+Fe2O mixture, and can match PREM densities for 53 mol% Fe2O. Our work has the potential to lead to a significant revision of the current understanding of the core's structure and composition. △ Less

Submitted 2 December, 2025; originally announced December 2025.

Comments: Under review

Electron-phonon coupling of one-dimensional (3,0) carbon nanotube

Authors: Zhenfeng Ouyang, Jing Jiang, Jian-Feng Zhang, Miao Gao, Kai Liu, Zhong-Yi Lu

Abstract: A very recent report claims that ambient-pressure high-temperature ($T_c$) superconductivity was found in boron-doped three-dimensional networks of carbon nanotubes (CNTs). Here, we systematically study the electron-phonon coupling (EPC) of one-dimensional (1D) (3,0) CNT under ambient pressure. Our results show that the EPC constant $λ$ of the undoped 1D (3,0) CNT is 0.70, and reduces to 0.44 afte… ▽ More A very recent report claims that ambient-pressure high-temperature ($T_c$) superconductivity was found in boron-doped three-dimensional networks of carbon nanotubes (CNTs). Here, we systematically study the electron-phonon coupling (EPC) of one-dimensional (1D) (3,0) CNT under ambient pressure. Our results show that the EPC constant $λ$ of the undoped 1D (3,0) CNT is 0.70, and reduces to 0.44 after 1.3 holes/cell doping. Further calculations show that the undoped (3,0) CNT is a two-gap superconductor with a superconducting $T_c$ $\sim$ 33 K under ambient pressure. Additionally, we identify three characteristic phonon modes with strong EPC, establishing that the pristine (3,0) CNT is a high-$T_c$ superconducting unit, and further suggest that searching for those superconducting units with strong EPC phonon mode would be an effective way to discover high-$T_c$ phonon-mediated superconductors. Our study not only provide a crucial and timely theoretical reference for the recent report regarding superconducting CNTs, but also uncover that the pristine (3,0) CNT hosts the highest record of superconducting $T_c$ among the elemental superconductors under ambient pressure. △ Less

Submitted 5 November, 2025; originally announced November 2025.

Comments: 6 pages, 5 figures, 1 table

High-performance thermochromic multilayer coatings with W-doped VO2 nanoparticles dispersed in SiO2 matrix prepared on glass at a low temperature

Authors: Jaroslav Vlcek, Michal Kaufman, Elnaz M. Nia, Jiri Houska, Jiechao Jiang, Radomir Cerstvy, Stanislav Haviar, Efstathios I. Meletis

Abstract: We report a high-performance thermochromic VO2-based coating prepared by using a three-step process, consisting of magnetron sputter depositions of SiO2 films and V-W films and their postannealing, on standard glass at a low substrate temperature of 350 °C without opening the vacuum chamber to atmosphere. It is formed by four layers of W-doped VO2 nanoparticles dispersed in SiO2 matrix. The coatin… ▽ More We report a high-performance thermochromic VO2-based coating prepared by using a three-step process, consisting of magnetron sputter depositions of SiO2 films and V-W films and their postannealing, on standard glass at a low substrate temperature of 350 °C without opening the vacuum chamber to atmosphere. It is formed by four layers of W-doped VO2 nanoparticles dispersed in SiO2 matrix. The coating exhibits a transition temperature of 33 °C with an integral luminous transmittance of 65.4% (low-temperature state) and 60.1% (high-temperature state), and a modulation of the solar energy transmittance of 15.3%. Such a combination of properties, together with the low temperature during preparation, fulfill the requirements for large-scale implementation on building glass and have not been reported yet. △ Less

Submitted 31 October, 2025; originally announced October 2025.

All-Electrical Self-Switching of van der Waals Chiral Antiferromagnet

Authors: Junlin Xiong, Jiawei Jiang, Yanwei Cui, Han Gao, Ji Zhou, Zijia Liu, KuiKui Zhang, Shaobo Cheng, Kehui Wu, Sang-Wook Cheong, Kai Chang, Zhongkai Liu, Hongxin Yang, Shi-Jun Liang, Bin Cheng, Feng Miao

Abstract: Antiferromagnets have garnered significant attention due to their negligible stray field and ultrafast magnetic dynamics, which are promising for high-density and ultrafast spintronic applications. Their dual functionality as both spin sources and information carriers could enable all-electrical self-induced switching of antiferromagnetic order, offering great potential for ultra-compact spintroni… ▽ More Antiferromagnets have garnered significant attention due to their negligible stray field and ultrafast magnetic dynamics, which are promising for high-density and ultrafast spintronic applications. Their dual functionality as both spin sources and information carriers could enable all-electrical self-induced switching of antiferromagnetic order, offering great potential for ultra-compact spintronic devices. However, related progress is still elusive. Here, we report the deterministic switching of chiral antiferromagnetic orders induced by charge current at zero external magnetic field in the van der Waals (vdW) magnetically intercalated transition metal dichalcogenide CoTa3S6. This system exhibits strong interactions between cobalt atom magnetic moment lattice and itinerant electrons within the metallic layers, as demonstrated by temperature-dependent angle-resolved photoemission, scanning tunneling spectroscopy, and topological Nernst effect measurements. Notably, the itinerant-localization interactions lead to current-induced chiral spin orbit torques as well as Ruderman-Kittel-Kasuya-Yosida (RKKY) exchange torques that interact with the localized magnetic moments, facilitating all-electrical switching of the chiral magnetic order in the CoTa3S6 flake. Our work opens a promising avenue for manipulating antiferromagnetic orders by delicately engineering the synergistic interactions between magnetic moments and itinerant electrons. △ Less

Submitted 20 October, 2025; originally announced October 2025.

Anomalous strain-dependent thermal conductivity in superelastic screw-dislocated graphites

Authors: Yu Li, Zhiqiang Zhao, Zhuhua Zhang, Yong-Wei Zhang, Jin-Wu Jiang

Abstract: The design of strain-stable, or even strain-enhanced thermal transport materials is critical for stable operation of high-performance electronic devices. However, most nanomaterials suffer from strain-induced degradation, with even minor tensile strains markedly reducing thermal conductivity. Here, we demonstrate that screw-dislocated graphites (SDGs), recently identified as topological semimetals… ▽ More The design of strain-stable, or even strain-enhanced thermal transport materials is critical for stable operation of high-performance electronic devices. However, most nanomaterials suffer from strain-induced degradation, with even minor tensile strains markedly reducing thermal conductivity. Here, we demonstrate that screw-dislocated graphites (SDGs), recently identified as topological semimetals, display an unusual increase in cross-plane thermal conductivity under both tensile and compressive strains, revealed by high-accuracy machine-learning-potential-driven non-equilibrium molecular dynamics. Notably, SDGs exhibit over 100% enhancement under tensile strains up to 80% along the dislocation axis, arising from strain-induced increase in dislocation interface tilt angle that elongates the effective heat transfer paths. Their thermal conductivity surpasses multilayer graphene by an order of magnitude. An analytical model is further derived linking thermal conductivity to dislocation number and strain, offering a predictive framework for designing strain-tunable screwdislocated structures. These findings highlight SDGs as a promising platform for high-performance electronic and wearable devices with tunable thermal properties. △ Less

Submitted 8 October, 2025; originally announced October 2025.

Comments: 12 pages, 7 figures

Boundaries Program Deformation in Isolated Active Networks

Authors: Zixiang Lin, Shichen Liu, Shahriar Shadkhoo, Jialong Jiang, Heun Jin Lee, David Larios, Chunhe Li, Hongyi Bian, Anqi Li, Rob Phillips, Matt Thomson, Zijie Qu

Abstract: Cellular structures must organize themselves within strict physical constraints, operating with finite resources and well-defined boundaries. Classical systems demonstrate only passive responses to boundaries, from surface energy minimization in soap films to strain distributions in elastic networks. Active matter fundamentally alters this paradigm - internally generated stresses create a bidirect… ▽ More Cellular structures must organize themselves within strict physical constraints, operating with finite resources and well-defined boundaries. Classical systems demonstrate only passive responses to boundaries, from surface energy minimization in soap films to strain distributions in elastic networks. Active matter fundamentally alters this paradigm - internally generated stresses create a bidirectional coupling between boundary geometry and mass conservation that enables dynamic control over network organization. Here we demonstrate boundary geometry actively directs network deformation in reconstituted microtubule-kinesin systems, revealing a programmable regime of shape transformation through controlled boundary manipulation. A coarse-grained theoretical framework reveals how boundary geometry couples to internal stress fields via mass conservation, producing distinct dynamical modes that enable engineered deformations. The emergence of shape-preserving and shape-changing regimes, predicted by theory and confirmed through experiments, establishes boundary geometry as a fundamental control parameter for active materials. The control principle based on boundaries advances both the understanding of biological organization and enables design of synthetic active matter devices with programmable deformation. △ Less

Submitted 2 October, 2025; originally announced October 2025.

Comments: arXiv admin note: substantial text overlap with arXiv:2101.08464

A Non-Equilibrium Dissipation Parameter and the Ideal Glass

Authors: Jun-Ying Jiang, Liang Gao, Hai-Bin Yu

Abstract: Glass materials, as quintessential non-equilibrium systems, exhibit properties such as energy dissipation that are highly sensitive to their preparation histories. A key challenge has been identifying a unified order parameter to rationalize these properties. Here, we demonstrate that a configurational distance metric can effectively collapse energy dissipation data across diverse preparation hist… ▽ More Glass materials, as quintessential non-equilibrium systems, exhibit properties such as energy dissipation that are highly sensitive to their preparation histories. A key challenge has been identifying a unified order parameter to rationalize these properties. Here, we demonstrate that a configurational distance metric can effectively collapse energy dissipation data across diverse preparation histories and testing protocols, including varying cooling rates, aging processes, probing times, and the amplitudes of mechanical excitation, as long as the temperature remains above the so-called ideal glass transition (where the extrapolated structural relaxation time diverges). Our results provide a unified description for the non-equilibrium dissipation and suggest that the putative concept of the ideal glass transition is imprinted in material characteristics △ Less

Submitted 27 September, 2025; originally announced September 2025.

Comments: 13 pages, 5 figures, pubilshed to Reports on Progress in Physics

Layer controlled orbital selective Mott transition in monolayer nickelate

Authors: Byungmin Sohn, Minjae Kim, Sangjae Lee, Wenzheng Wei, Juan Jiang, Fengmiao Li, Sergey Gorovikov, Marta Zonno, Tor Pedersen, Sergey Zhdanovich, Ying Liu, Huikai Cheng, Ke Zou, Yu He, Sohrab Ismail-Beigi, Frederick J. Walker, Charles H. Ahn

Abstract: Dimensionality and electronic correlations are crucial elements of many quantum material properties. An example is the change of the electronic structure accompanied by the loss of quasiparticles when a metal is reduced from three dimensions to a lower dimension, where the Coulomb interaction between carriers becomes poorly screened. Here, using angle-resolved photoemission spectroscopy (ARPES), w… ▽ More Dimensionality and electronic correlations are crucial elements of many quantum material properties. An example is the change of the electronic structure accompanied by the loss of quasiparticles when a metal is reduced from three dimensions to a lower dimension, where the Coulomb interaction between carriers becomes poorly screened. Here, using angle-resolved photoemission spectroscopy (ARPES), we report an orbital-selective decoherence of spectral density in the perovskite nickelate LaNiO3 towards the monolayer limit. The spectral weight of the dz2 band vanishes much faster than that of the dx2-y2 band as the thickness of the LaNiO3 layer is decreased to a single unit cell, indicating a stronger correlation effect for the former upon dimensional confinement. Dynamical mean-field theory (DMFT) calculations show an orbital-selective Mott transition largely due to the localization of dz2 electrons along the c axis in the monolayer limit. This orbital-selective correlation effect underpins many macroscopic properties of nickelates, such as metal-to-insulator transition and superconductivity, where most theories are built upon a dx2-y2-dz2 two-band model. △ Less

Submitted 23 September, 2025; originally announced September 2025.

Going beyond Landauer: Information-cost relations from inference based on the maximum entropy principle

Authors: Yuanyuan Xiao, Jian-Hua Jiang, Junjie Liu

Abstract: The Landauer's principle, a cornerstone of information thermodynamics, provides a fundamental lower bound on the energetic cost of information erasure in terms of the information content change. However, its traditional formulation is largely confined to systems exchanging solely energy with an ideal thermal bath. In this work, we derive general information-cost trade-off relations that go beyond… ▽ More The Landauer's principle, a cornerstone of information thermodynamics, provides a fundamental lower bound on the energetic cost of information erasure in terms of the information content change. However, its traditional formulation is largely confined to systems exchanging solely energy with an ideal thermal bath. In this work, we derive general information-cost trade-off relations that go beyond the scope of Landauer's principle by developing a thermodynamic inference approach based on the maximum entropy principle. These relations require only information about the system and are applicable to complex quantum scenarios involving multiple conserved charges and non-thermal environments. Specifically, we present two key results: (i) In scenarios where only the mean values of observables are accessible, we derive an information-content-informed upper bound on the thermodynamic cost which complements an existing generalized Landauer lower bound. (ii) When second-order fluctuations can also be measured, we obtain an information-content-informed lower bound on the change in variances of observables, thereby extending the Landauer's principle to constrain higher-order fluctuation costs. We numerically validate our information-cost trade-off relations using a coupled-qubit system exchanging energy and excitations, a driven qubit implementing an information erasure process, and a driven double quantum dot system that can operate as an inelastic heat engine. Our results underscore the broad utility of maximum-entropy inference in constraining thermodynamic costs for generic finite-time quantum processes, with direct relevance to quantum information processing and quantum thermodynamic applications. △ Less

Submitted 9 November, 2025; v1 submitted 21 September, 2025; originally announced September 2025.

Comments: 15 pages, 4 figures, comments are welcome!

Prediction of Li3Fe8B8 compound with rapid one-dimensional ion diffusion channels

Authors: Shiya Chen, Paul Oftedahl, Zhen Zhang, Zepeng Wu, Junjie Jiang, Vladimir Antropov, Julia V. Zaikina, Shunqing Wu, Kai-Ming Ho, Yang Sun

Abstract: Using a computational crystal structure search in the Li-Fe-B ternary system, we predict a stable phase of Li3Fe8B8, featuring 1D channels that enable rapid Li-ion transport. Ab initio molecular dynamics simulations show that the Li-ion diffusion coefficient in Li3Fe8B8 surpasses that of common electrode and conductive additive materials by several orders of magnitude. The high diffusion in Li3Fe8… ▽ More Using a computational crystal structure search in the Li-Fe-B ternary system, we predict a stable phase of Li3Fe8B8, featuring 1D channels that enable rapid Li-ion transport. Ab initio molecular dynamics simulations show that the Li-ion diffusion coefficient in Li3Fe8B8 surpasses that of common electrode and conductive additive materials by several orders of magnitude. The high diffusion in Li3Fe8B8 can be explained by the Frenkel-Kontorova model, which describes an incommensurate state between the Li diffusion chain and the periodic potential field caused by the FeB backbone structure. The favorable lithium-ion diffusivity and mechanical properties of Li3Fe8B8 make it a promising conductive additive for battery materials. Its itinerant ferromagnetism also offers a platform for exploring correlated-electron magnetism and spin-dependent phenomena. △ Less

Submitted 19 September, 2025; originally announced September 2025.

Journal ref: Phys. Rev. Materials 9, 105403 (2025)

Superconductivity in W3Re2C with chiral structure

Authors: Lei Yang, Jing Jiang, Hui-Hui He, Kai Liu, Hechang Lei

Abstract: We discover superconductivity in cubic W3Re2C with chiral structure and the superconducting transition temperature Tc is about 6.2 K. Detailed characterizations and analysis indicate that W3Re2C is a bulk type-II BCS superconductor with full isotropic gap. Moreover, first-principles calculations indicate that the electron-phonon coupling primarily arises from interactions between W/Re 5d electroni… ▽ More We discover superconductivity in cubic W3Re2C with chiral structure and the superconducting transition temperature Tc is about 6.2 K. Detailed characterizations and analysis indicate that W3Re2C is a bulk type-II BCS superconductor with full isotropic gap. Moreover, first-principles calculations indicate that the electron-phonon coupling primarily arises from interactions between W/Re 5d electronic states and their low-frequency phonons. Furthermore, the breaking of inversion symmetry in W3Re2C facilitates the emergence of Weyl points in the electronic structure. Therefore, W3Re2C can serve as a promising platform for investigating the influences of chiral structure on both superconductivity and band topology. △ Less

Submitted 18 September, 2025; originally announced September 2025.

Comments: 7 pages and 5 figures

Intrinsic characteristic radius drives phonon anomalies in Janus transition metal dichalcogenide nanotubes

Authors: Jing-Jing Zhang, Jin-Wu Jiang

Abstract: Transition metal dichalcogenides and their derivatives offer a versatile platform for exploring novel structural and functional properties in low-dimensional materials. In particular, Janus monolayers possess an intrinsic out-of-plane asymmetry that induces a built-in bending radius, which can strongly influence their physical behavior. In this work, we investigate the tubular structures formed by… ▽ More Transition metal dichalcogenides and their derivatives offer a versatile platform for exploring novel structural and functional properties in low-dimensional materials. In particular, Janus monolayers possess an intrinsic out-of-plane asymmetry that induces a built-in bending radius, which can strongly influence their physical behavior. In this work, we investigate the tubular structures formed by rolling Janus monolayers into the Janus nanotube with an extrinsic radius. Using a combination of atomistic simulations and continuum mechanics, we identify that the total energy of the Janus nanotube is minimized when the tube radius equals to the intrinsic bending radius of the Janus monolayer. An analytical expression for this characteristic radius is derived, providing a theoretical basis for understanding the stability of Janus nanotubes. Furthermore, we find that the optical phonon modes in these Janus nanotubes exhibit an anomalous dependence on the tube radius; i.e., their frequencies reach a maximum value near the characteristic radius, in contrast to the monotonic increase of optical phonon frequencies with radius in conventional nanotubes. The phonon anomaly is due to the soft phonon mode effect induced by the deviation from the most stable tubular configuration with the characteristic radius. These results uncover a unique coupling between intrinsic and extrinsic curvature in Janus systems and open new pathways for tuning vibrational and other properties in curved low-dimensional materials. △ Less

Submitted 18 September, 2025; originally announced September 2025.

Comments: 22 pages, 11 figures

Strong Raman Optical Activity and Chiral Phonons in Chiral Hybrid Organic-Inorganic Perovskites

Authors: Evan W. Muller, Aleksey Ruditskiy, Jie Jiang, Thuc T. Mai, Katherine Burzynski, Ruth Pachter, Michael F. Durstock, W. Joshua Kennedy, Rahul Rao

Abstract: Hybrid organic-inorganic perovskites with chiral organic cations are very interesting for optoelectronic applications because of their intrinsically chiral light-matter interactions. Chiral distortions in these materials lead to circular dichroism, circular birefringence, and circularly polarized luminescence in the band transitions of the inorganic sublattice. Raman-active vibrational modes in th… ▽ More Hybrid organic-inorganic perovskites with chiral organic cations are very interesting for optoelectronic applications because of their intrinsically chiral light-matter interactions. Chiral distortions in these materials lead to circular dichroism, circular birefringence, and circularly polarized luminescence in the band transitions of the inorganic sublattice. Raman-active vibrational modes in these crystals are governed by crystal symmetry and therefore are also strongly impacted by the nature and magnitude of the chiral distortions. Here, we report low-frequency Raman modes that are sensitive to circularly polarized excitation in chiral hybrid organic-inorganic perovskites (CHOIPs) across a wide range of structures and compositions. The circularly polarized Raman spectra from enantiomers of CHOIP single crystals exhibit sharp modes below 150 cm-1, corresponding to vibrations of the lead iodide octahedra. These modes exhibit strong differences in intensities (Raman optical activity, ROA) depending on the handedness of the excitation, with high degree of polarization for several modes. Calculations reveal the presence of several chiral phonon modes with opposite phonon angular momenta. The strong ROA and the chiral phonon modes are a direct consequence of chirality transfer from the chiral organic linker to the lead iodide octahedra in the CHOIP structure, resulting in a strong chiroptical response in the phonon modes. △ Less

Submitted 27 August, 2025; originally announced August 2025.

Comments: 6 Figures

Jahn-Teller-like Distortion in a One-dimensional π-Conjugated Polymer

Authors: Ziyi Wang, Boyu Qie, Weichen Tang, Jingwei Jiang, Fujia Liu, Peter H. Jacobse, Jiaming Lu, Xinheng Li, Steven G. Louie, Felix R. Fischer, Michael F. Crommie

Abstract: Structurally distorting low-dimensional π-conjugated systems can profoundly influence their electronic properties, but controlling such behavior in extended-width systems remains challenging. Here we demonstrate that a one-dimensional conjugated polymer, poly-(difluorenoheptalene-ethynylene) (PDFHE), undergoes a pronounced out-of-plane backbone distortion, equivalent to a spontaneous symmetry brea… ▽ More Structurally distorting low-dimensional π-conjugated systems can profoundly influence their electronic properties, but controlling such behavior in extended-width systems remains challenging. Here we demonstrate that a one-dimensional conjugated polymer, poly-(difluorenoheptalene-ethynylene) (PDFHE), undergoes a pronounced out-of-plane backbone distortion, equivalent to a spontaneous symmetry breaking (SSB) of its mirror symmetry. We synthesized PDFHE on noble metal surfaces and characterized its structure and electronic states using low-temperature scanning tunneling microscopy. Rather than adopting a planar, high-symmetry conformation, PDFHE relaxes into non-planar isomers stabilized by a Jahn-Teller-like mechanism that relieves an electronic instability relative to the gapped planar structure. Density functional theory calculations corroborate these findings, revealing that distortion lowers the total polymer energy and enlarges the bandgap, providing a microscopic explanation for the SSB. Our results show that even in mechanically robust extended π-systems, subtle electron-lattice coupling can spontaneously drive significant structural rearrangements. △ Less

Submitted 20 August, 2025; originally announced August 2025.

Comments: 16 pages, 4 figures

Sliding two-dimensional superconductivity and charge-density-wave state in a bulk crystal

Authors: Xiangqi Liu, Chen Xu, Jing Jiang, Haonan Wang, Shaobo Liu, Gan Liu, Ziyi Zhu, Jian Yuan, Wei Xia, Lianbing Wen, Jiawei Luo, Yixuan Luo, Xia Wang, Na Yu, Peihong Cheng, Leiming Chen, Rui Zhou, Jun Li, Yulin Chen, Shiwei Wu, Ke Qu, Wei Li, Guangming Zhang, Chungang Duan, Jianhao Chen , et al. (4 additional authors not shown)

Abstract: Superconductivity in the two-dimensional (2D) limit is a fertile ground for exotic quantum phenomena-many of which remain elusive in their 3D counterparts. While studies of 2D superconductivity have predominantly focused on mono- or few-layer systems, we demonstrate an alternative route-interlayer sliding in bulk crystals. Through a precisely controlled growth strategy, we engineer interlayer slid… ▽ More Superconductivity in the two-dimensional (2D) limit is a fertile ground for exotic quantum phenomena-many of which remain elusive in their 3D counterparts. While studies of 2D superconductivity have predominantly focused on mono- or few-layer systems, we demonstrate an alternative route-interlayer sliding in bulk crystals. Through a precisely controlled growth strategy, we engineer interlayer sliding in bulk 3R-NbSe2, deliberately disrupting [001] mirror symmetry and drastically suppressing interlayer coupling. Remarkably, this structural manipulation stabilizes Ising-type superconductivity coexisting with an unconventional charge-density-wave (CDW) state akin to that of monolayer 2H-NbSe2. The sliding phase exhibits a pronounced suppression of the upper critical field at low temperatures, revealing a delicate competition between Ising and Rashba spin-orbit coupling (SOC) in the globally noncentrosymmetric lattice. Intriguingly, the superconducting state displays two-fold symmetry, a signature that may arise from asymmetric SOC or a multi-component pairing order parameter. Our work establishes interlayer sliding as a symmetry-breaking tool to promote 2D superconductivity in bulk materials-without resorting to extrinsic intercalation or doping. More broadly, this approach sets a paradigm for unlocking hidden quantum states in layered materials, offering a new dimension in design of quantum matter. △ Less

Submitted 2 August, 2025; originally announced August 2025.

Comments: Main Text 36 Pages + 3 figures; SI 38 pages + 30 figures + 8 tables

An eco-friendly universal strategy via ribavirin to achieve highly efficient and stable perovskite solar cells

Authors: Xianhu Wu, Gaojie Xia, Guanglei Cui, Jieyu Bi, Nian Liu, Jiaxin Jiang, Jilong Sun, Luyang Liu, Ping Li, Ning Lu, Zewen Zuo, Min Gu

Abstract: The grain boundaries of perovskite films prepared by the solution method are highly disordered, with a large number of defects existing at the grain boundaries. These defect sites promote the decomposition of perovskite. Here, we use ribavirin obtained through bacillus subtilis fermentation to regulate the crystal growth of perovskite, inducing changes in the work function and energy level structu… ▽ More The grain boundaries of perovskite films prepared by the solution method are highly disordered, with a large number of defects existing at the grain boundaries. These defect sites promote the decomposition of perovskite. Here, we use ribavirin obtained through bacillus subtilis fermentation to regulate the crystal growth of perovskite, inducing changes in the work function and energy level structure of perovskite, which significantly reduces the defect density. Based on density functional theory calculations, the defect formation energies of VI, VMA, VPb, and PbI in perovskite are improved. This increases the open-circuit voltage of perovskite solar cells (PSCs) (ITO/PEDOT:PSS/perovskite/PCBM/BCP/Ag) from 1.077 to 1.151 V, and the PCE increases significantly from 17.05% to 19.86%. Unencapsulated PSCs were stored in the environment (humidity approximately 35+-5%) for long-term stability testing. After approximately 900 hours of storage, the PCE of the ribavirin-based device retains 84.33% of its initial PCE, while the control-based device retains only 13.44% of its initial PCE. The PCE of PSCs (ITO/SnO2/perovskite/Spiro-OMETAD/Ag) is increased from 20.16% to 22.14%, demonstrating the universality of this doping method. This universal doping strategy provides a new approach for improving the efficiency and stability of PSCs using green molecular doping strategies. △ Less

Submitted 2 July, 2025; originally announced July 2025.

Signature of gate tunable superconducting network in twisted bilayer graphene

Authors: Yingbo Wang, Yingzhuo Han, Lu Cao, Xun-Jiang Luo, Yucheng Xue, Jiefei Shi, Xiaomeng Wang, Xiangjia Bai, Junnan Jiang, Ziyi Tian, Kenji Watanabe, Takashi Taniguchi, Fengcheng Wu, Qing-feng Sun, Hong-Jun Gao, Yuhang Jiang, Jinhai Mao

Abstract: Twisted van der Waals materials provide a tunable platform for investigating two-dimensional superconductivity and quantum phases. Using spectra-imaging scanning tunneling microscopy, we study the superconducting states in twisted bilayer graphene and track their evolution from insulating phases. Gate-dependent spectroscopic measurements reveal two distinct regimes: under-doped (ν = -2.3) and opti… ▽ More Twisted van der Waals materials provide a tunable platform for investigating two-dimensional superconductivity and quantum phases. Using spectra-imaging scanning tunneling microscopy, we study the superconducting states in twisted bilayer graphene and track their evolution from insulating phases. Gate-dependent spectroscopic measurements reveal two distinct regimes: under-doped (ν = -2.3) and optimally doped (ν = -2.6). In the under-doped regime, partial superconductivity arises, forming a network interspersed with non-gapped regions. At optimal doping, the entire unit cell demonstrates superconductivity, with gap size modulation showing an anti-correlation with the local density of states. This gate-dependent transition from an insulating phase to a modulated superconductor uncovers an unexpected spatial hierarchy in pairing behavior and offers direct microscopic insights to constrain theories of superconductivity in moiré systems. △ Less

Submitted 6 July, 2025; originally announced July 2025.

Comments: 18 pages, 4 figures

Synthesis and transport properties of epitaxial Bi (111) films on GaAs (111) substrates

Authors: Jagannath Jena, Eugene D. Ark, Siddhesh Ambhire, Michael D. Smith, Justin S. Wood, Junyi Yang, John Pearson, Hanu Arava, Daniel Rosenmann, Ulrich Welp, Jidong S. Jiang, Deshun Hong, Ivar Martin, Steven S. -L. Zhang, Anand Bhattacharya

Abstract: In recent decades, the growth of ultrathin epitaxial bismuth (Bi) films on various substrates has garnered interest due to their unique electronic properties. We report upon the growth and electrical transport properties of epitaxial Bi (111) films in the thickness range of 5-32 nm deposited directly on GaAs (111) substrates, without a buffer layer. The quality of Bi films is found to depend on co… ▽ More In recent decades, the growth of ultrathin epitaxial bismuth (Bi) films on various substrates has garnered interest due to their unique electronic properties. We report upon the growth and electrical transport properties of epitaxial Bi (111) films in the thickness range of 5-32 nm deposited directly on GaAs (111) substrates, without a buffer layer. The quality of Bi films is found to depend on conditions for substrate treatment using Ar+ ion-milling and annealing. Substrates milled at low ion beam currents display poor surface reconstruction after annealing, which hinders the growth of high-quality films. In contrast, substrates milled under optimized conditions led to reconstructed surfaces upon annealing, resulting in epitaxial Bi films with predominantly single-domain orientation. Although epitaxial films formed in both cases, transport measurements indicated significantly higher conductivity for films grown on optimally treated substrates. Measurements at low temperatures suggest that the transport properties are dominated by a surface state with high mobility electrons. Magneto-transport measurements suggest that conductivity and mobility improve progressively with increasing film thickness. For the thinnest 5 nm film, a hole-like state emerges, presumably as the electron-like state is gapped out. These results provide a robust methodology for growing high-quality epitaxial Bi films on GaAs (111) and offer insights into their unique transport properties, and our ability to tune them. △ Less

Submitted 9 October, 2025; v1 submitted 4 July, 2025; originally announced July 2025.

Quasiconservation Laws and Suppressed Transport in Weakly Interacting Localized Models

Authors: Jessica Kaijia Jiang, Federica Maria Surace, Olexei I. Motrunich

Abstract: The stability of localization in the presence of interactions remains an open problem, with finite-size effects posing significant challenges to numerical studies. In this work, we investigate the perturbative stability of noninteracting localization under weak interactions, which allows us to analyze much larger system sizes. Focusing on disordered Anderson and quasiperiodic Aubry-André models in… ▽ More The stability of localization in the presence of interactions remains an open problem, with finite-size effects posing significant challenges to numerical studies. In this work, we investigate the perturbative stability of noninteracting localization under weak interactions, which allows us to analyze much larger system sizes. Focusing on disordered Anderson and quasiperiodic Aubry-André models in one dimension, and using the adiabatic gauge potential (AGP) at first order in perturbation theory, we compute first-order corrections to noninteracting local integrals of motion (LIOMs). We find that for at least an $O(1)$ fraction of the LIOMs, the corrections are well-controlled and converge at large system sizes, while others suffer from resonances. Additionally, we introduce and study the charge-transport capacity of this weakly interacting model. To first order, we find that the charge transport capacity remains bounded in the presence of interactions. Taken together, these results demonstrate that localization is perturbatively stable to weak interactions at first order, implying that, at the very least, localization persists for parametrically long times in the inverse interaction strength. We expect this perturbative stability to extend to all orders at sufficiently strong disorder, where the localization length is short, representing the true localized phase. Conversely, our findings suggest that the previously proposed interaction-induced avalanche instability, namely in the weakly localized regime of the Anderson and Aubry-André models, is a more subtle phenomenon arising only at higher orders in perturbation theory or through nonperturbative effects. △ Less

Submitted 3 November, 2025; v1 submitted 3 July, 2025; originally announced July 2025.

Comments: 37 pages, 27 figures

The interplay of ferroelectricity and magneto-transport in non-magnetic moiré superlattices

Authors: Siqi Jiang, Renjun Du, Jiawei Jiang, Gan Liu, Jiabei Huang, Yu Du, Yaqing Han, Jingkuan Xiao, Di Zhang, Fuzhuo Lian, Wanting Xu, Siqin Wang, Lei Qiao, Kenji Watanabe, Takashi Taniguchi, Xiaoxiang Xi, Wei Ren, Baigeng Wang, Alexander S. Mayorov, Kai Chang, Hongxin Yang, Lei Wang, Geliang Yu

Abstract: The coupling of ferroelectricity and magnetic order provides rich tunability for engineering material properties and demonstrates great potential for uncovering novel quantum phenomena and multifunctional devices. Here, we report interfacial ferroelectricity in moiré superlattices constructed from graphene and hexagonal boron nitride. We observe ferroelectric polarization in an across-layer moiré… ▽ More The coupling of ferroelectricity and magnetic order provides rich tunability for engineering material properties and demonstrates great potential for uncovering novel quantum phenomena and multifunctional devices. Here, we report interfacial ferroelectricity in moiré superlattices constructed from graphene and hexagonal boron nitride. We observe ferroelectric polarization in an across-layer moiré superlattice with an intercalated layer, demonstrating a remnant polarization comparable to its non-intercalated counterpart. Remarkably, we reveal a magnetic-field enhancement of ferroelectric polarization that persists up to room temperature, showcasing an unconventional amplification of ferroelectricity in materials lacking magnetic elements. This phenomenon, consistent across devices with varying layer configurations, arises purely from electronic rather than ionic contributions. Furthermore, the ferroelectric polarization in turn modulates quantum transport characteristics, suppressing Shubnikov-de Haas oscillations and altering quantum Hall states in polarized phases. This interplay between ferroelectricity and magneto-transport in non-magnetic materials is crucial for exploring magnetoelectric effects and advancing two-dimensional memory and logic applications. △ Less

Submitted 1 July, 2025; originally announced July 2025.

Journal ref: Nature Communications, volume 16, Article number: 5640 (2025)

Global-Local Duality of Energetic Control Cost in Multipartite Quantum Correlated Systems

Authors: Rui Guan, Junjie Liu, Jian-Hua Jiang

Abstract: Multipartite quantum correlated systems (MQCSs) are widely utilized in diverse quantum information tasks, where their sophisticated control inherently incurs energetic costs. However, the fundamental characteristics of these control costs remain elusive, largely due to the lack of thermodynamic descriptions capable of capturing the full complexities of MQCSs. Here, we uncover universal thermodynam… ▽ More Multipartite quantum correlated systems (MQCSs) are widely utilized in diverse quantum information tasks, where their sophisticated control inherently incurs energetic costs. However, the fundamental characteristics of these control costs remain elusive, largely due to the lack of thermodynamic descriptions capable of capturing the full complexities of MQCSs. Here, we uncover universal thermodynamic relations for arbitrary MQCSs weakly coupled to a thermal bath, establishing an intrinsic global-local duality of control costs. Using these relations, we elucidate the exact role of multipartite correlation--a defining quantum feature of MQCSs--in shaping control costs at finite times. We also demonstrate that the relative magnitude between global and local control costs is undetermined, which perplexes the cost management of MQCSs under finite-time controls. Our results are numerically corroborated with applications to experimentally realizable multi-qubit systems undergoing finite-time qubit reset processes. △ Less

Submitted 27 May, 2025; originally announced May 2025.

Comments: Accepted by Physical Review Research, in press

Unconventional band splitting of CeSb in the devil's staircase transition

Authors: Tongrui Li, Zhanfeng Liu, Peng Li, Yuzhe Wang, Zhisheng Zhao, Shiwu Su, Zhicheng Jiang, Yuhao Hong, Hui Tian, Xin Zheng, Yi Liu, Yilin Wang, Zhengtai Liu, Dawei Shen, Zhe Sun, Yang Liu, Juan Jiang, Donglai Feng

Abstract: The interplay between magnetism and electronic band structure is a central theme in condensed matter physics. CeSb, with its complex devil's staircase antiferromagnetic transition, offers a unique opportunity to explore this interplay. Using angle-resolved photoemission spectroscopy (ARPES), we investigate the electronic structure evolution across the devil's staircase transition. Upon entering th… ▽ More The interplay between magnetism and electronic band structure is a central theme in condensed matter physics. CeSb, with its complex devil's staircase antiferromagnetic transition, offers a unique opportunity to explore this interplay. Using angle-resolved photoemission spectroscopy (ARPES), we investigate the electronic structure evolution across the devil's staircase transition. Upon entering the antiferromagnetic phase, we observe an intriguing band splitting of the electron pocket around the X point. The energy separation between the split bands changes abruptly with temperature, consistent with the characteristics of the first-order phase transition. However, their respective spectral weights behave gradually with temperature. Combined with our density functional theory (DFT) calculations, we suggest that this atypical behavior deviates from conventional magnetically induced band splitting and potentially arises from the intricate modulation of paramagnetic and antiferromagnetic layers within the devil's staircase transition. Our results provide insights into the complex relationship between electronic structure and magnetism in correlated electron systems. △ Less

Submitted 18 May, 2025; originally announced May 2025.

Comments: 13 pages, 4 figures

Journal ref: Communications Materials volume 6, Article number: 97 (2025)

Defect engineering and effect of vacancy concentration on the electrochemical performance of V-based MXenes

Authors: Leiqiang Qin, Rutuparna Samal, Jianxia Jiang, Joseph Halim, Ningjun Chen, Florian Chabanais, Per O. A. Persson, Johanna Rosen

Abstract: Vacancies play a pivotal role in determining the physical and chemical properties of materials. Introducing vacancies into two-dimensional (2D) materials offers a promising strategy for developing high-performance electrode materials for electrochemical energy storage. Herein, a facile top-down strategy is employed to create V-based MXenes with tunable vacancy concentrations, achieved by designing… ▽ More Vacancies play a pivotal role in determining the physical and chemical properties of materials. Introducing vacancies into two-dimensional (2D) materials offers a promising strategy for developing high-performance electrode materials for electrochemical energy storage. Herein, a facile top-down strategy is employed to create V-based MXenes with tunable vacancy concentrations, achieved by designing the precursor (V1-xCrx)2AlC (x=0.05, 0.1, 0.3) MAX phase and precisely controlling the etching process. Systematic investigations reveal that introducing a moderate concentration of Cr-induced vacancies significantly enhances both the capacitance and rate performance of V-based MXenes. Specifically, V1.9CTz achieves a capacitance of 760 F g-1, far exceeding the 420 F g-1 of vacancy-free V2CTz MXene. In contrast, an excessively high vacancy concentration lead to deteriorated electrochemical performance and compromised structural stability. This work illustrates that defect engineering is a powerful approach to tailor the electrochemical properties of MXenes, offering a framework for designing next-generation MXene-based energy storage systems. △ Less

Submitted 7 May, 2025; originally announced May 2025.

Phase stabilization of In2Se3 by disordered Ni intercalation and its enhanced thermoelectrical performance

Authors: Zengguang Shi, Yukun Xiao, Mian Li, Jianfeng Cai, Yanmei Chen, Jun Jiang, Xiaoping Ouyang, Zhifang Chai, Qing Huang

Abstract: Van der Waals (vdW) layered materials have gained significant attention owing to their distinctive structure and unique properties. The weak interlayer bonding in vdW layered materials enables guest atom intercalation, allowing precise tuning of their physical and chemical properties. In this work, a ternary compound, NixIn2Se3 (x = 0-0.3), with Ni randomly occupying the interlayers of In2Se3, was… ▽ More Van der Waals (vdW) layered materials have gained significant attention owing to their distinctive structure and unique properties. The weak interlayer bonding in vdW layered materials enables guest atom intercalation, allowing precise tuning of their physical and chemical properties. In this work, a ternary compound, NixIn2Se3 (x = 0-0.3), with Ni randomly occupying the interlayers of In2Se3, was synthesized via an intercalation route driven by electron injection. The intercalated Ni atoms act as anchor points within the interlayer of In2Se3, which effectively suppresses the phase transition of In2Se3 at elevated temperatures. Furthermore, the disordered Ni intercalation significantly enhanced the electrical conductivity of In2Se3 through electron injection, while reducing the thermal conductivity due to the interlayer phonon scattering, leading to an improved thermoelectric performance. For instance, the thermoelectric figure of merit (ZT) of Ni0.3In2Se3 increased by 86% (in-plane) and 222% (out-of-plane) compared to In2Se3 at 500 oC. These findings not only provide an effective strategy to enhance the performance of layered thermoelectric materials, but also demonstrate the potential of intercalation chemistry for expanding the application scope of van der Waals (vdW) layered materials. △ Less

Submitted 23 April, 2025; originally announced April 2025.

Domain Wall Sliding-induced Polarization Switching in Multilayer Graphene

Authors: Zhou Zhou, Xiyao Peng, Jianfeng Bi, Fei Xue, Jie Jiang, Huizhen Wu, Zhiwen Shi, Haoliang Qian, Toshikaze Kariyado, Sihan Zhao

Abstract: Electric polarization and metallicity are long believed not to coexist until the emergence of exceptionally rare material examples including the bulk polar metals and more recently two-dimensional (2D) van der Waals (vdW) materials such as 1T' WTe2. The electric polarization for the latter represents a new and distinguishable paradigm in materials science and physics because its electric polarizat… ▽ More Electric polarization and metallicity are long believed not to coexist until the emergence of exceptionally rare material examples including the bulk polar metals and more recently two-dimensional (2D) van der Waals (vdW) materials such as 1T' WTe2. The electric polarization for the latter represents a new and distinguishable paradigm in materials science and physics because its electric polarization states embedded in the conduction electron sea are able to couple with (and controlled by) the external electric field. However, the microscopic polarization switching process and mechanism in these 2D vdW metallic materials have not been experimentally observed and remain elusive. Here, we report the first direct experimental imaging of the microscopic mechanism behind electric-field-coupled polarization switching in a metallic system. Our gate-tunable nanoscale optical imaging identifies the robust coexistence of electric polarization and appreciable carrier densities in adjacent polar domains hosting opposite electric polarizations in a 2D elemental metallic material, tetralayer graphene. We directly visualize and verify that the sliding domain wall (DW) solitons confined at the middlemost interface are responsible for the polarization switching in tetralayer graphene upon the application of electric fields and mechanical forces. Our work provides the first direct visualization of domain wall sliding-induced polarization switching in 2D elemental carbon at room temperature, significantly expanding and advancing the research of "ferroelectric metal" initially dubbed by P. W. Anderson and coauthors in 1965. △ Less

Submitted 10 October, 2025; v1 submitted 9 April, 2025; originally announced April 2025.

Comments: 39 pages; 4 figures, 21 supplementary data figures, etc

Machine Learning Assisted Modeling of Amorphous TiO$_2$-Doped GeO$_2$ for Advanced LIGO Mirror Coatings

Authors: Jun Jiang, Rui Zhang, Kiran Prasai, Riccardo Bassiri, James N. Fry, Martin M. Fejer, Hai-Ping Cheng

Abstract: The mechanical loss angle of amorphous TiO$_2$-doped GeO$_2$ can be lower than 10$^{-4}$, making it a candidate for Laser Interferometer Gravitational-wave Observatory (LIGO) mirror coatings. Amorphous oxides have complex atomic structures that are influenced by various factors, including doping concentration, preparation, and thermal history, resulting in different mass densities and physical pro… ▽ More The mechanical loss angle of amorphous TiO$_2$-doped GeO$_2$ can be lower than 10$^{-4}$, making it a candidate for Laser Interferometer Gravitational-wave Observatory (LIGO) mirror coatings. Amorphous oxides have complex atomic structures that are influenced by various factors, including doping concentration, preparation, and thermal history, resulting in different mass densities and physical properties. Modeling at atomistic level enables capturing these effects by generating atomic structure models according to experimental conditions. In order to obtain reliable and physical amorphous models at an affordable cost, we develop classical and machine-learning potentials (MLP) to speed up simulations. First-principles calculations are used to train and validate MLP as well as validating structure models. To better reproduce properties such as elastic modulus, radial distribution function (RDF) and the variations in mass density of doped amorphous oxides, density functional theory (DFT) calculations are used to optimize the final models. We find that the mass densities of amorphous systems are correlated with the total void volume. The experimental mass density matches the models with the most symmetric potential energy wells under volume change. The elastic response of the metal-oxygen network is also studied. The 27\% TiO$_2$ doped GeO$_2$ system shows the least number of large atom-atom distance changes, while for 44\% TiO$_2$ doped GeO$_2$, a majority of Ti-O distances are significantly changed. In response to strains, the metal-oxygen network at low mass densities prefers to adjust bond angles, while at high mass densities, the adjustment is mainly done by changing atom-atom distance. △ Less

Submitted 27 March, 2025; originally announced March 2025.

Comments: 8 pages, 5 figures, under review and revision PRM

Anomalous Meets Topological Hall Effect in Cr2Ge2Te6 Heterostructures

Authors: Xiaofan Cai, Yaqing Han, Jiawei Jiang, Renjun Du, Di Zhang, Jiabei Huang, Siqi Jiang, Jingkuan Xiao, Zihao Wang, Qian Guo, Wanting Xu, Fuzhuo Lian, Siqing Wang, Bingxian Ou, Yongqiang Yang, Kenji Watanabe, Takashi Taniguchi, Alexander S. Mayorov, Konstantin S. Novoselov, Baigeng Wang, Kai Chang, Hongxin Yang, Lei Wang, Geliang Yu

Abstract: Introducing topologically protected skyrmions in graphene holds significant importance for developing high-speed, low-energy spintronic devices. Here, we present a centrosymmetric ferromagnetic graphene/trilayer Cr2Ge2Te6/graphene heterostructure, demonstrating the anomalous and topological Hall effect due to the magnetic proximity effect. Through gate voltage control, we effectively tune the emer… ▽ More Introducing topologically protected skyrmions in graphene holds significant importance for developing high-speed, low-energy spintronic devices. Here, we present a centrosymmetric ferromagnetic graphene/trilayer Cr2Ge2Te6/graphene heterostructure, demonstrating the anomalous and topological Hall effect due to the magnetic proximity effect. Through gate voltage control, we effectively tune the emergence and size of skyrmions. Micromagnetic simulations reveal the formation of skyrmions and antiskyrmions, which respond differently to external magnetic fields, leading to oscillations in the topological Hall signal. Our findings provide a novel pathway for the formation and manipulation of skyrmions in centrosymmetric two-dimensional magnetic systems, offering significant insights for developing topological spintronics. △ Less

Submitted 11 March, 2025; v1 submitted 10 March, 2025; originally announced March 2025.

Comments: There is a dispute over the ownership of the intellectual property involved. Differences exist with collaborators, research institutions, or other relevant parties regarding the ownership and use of the research results

Revealing the electron-spin fluctuation coupling by photoemission in CaKFe4As4

Authors: Peng Li, Yuzhe Wang, Yabin Liu, Jianghao Yao, Zhisheng Zhao, Zhengtai Liu, Dawei Shen, Huiqian Luo, Guanghan Cao, Juan Jiang, Donglai Feng

Abstract: Electron-boson coupling in unconventional superconductors is one of the key parameters in understanding the superconducting pairing symmetry. Here, we report definitive photoemission evidence of electron-spin exciton coupling in the iron-based superconductor CaKFe4As4, obtained via high-resolution ARPES. Our study identifies a distinct kink structure on the α band, observable only in the supercond… ▽ More Electron-boson coupling in unconventional superconductors is one of the key parameters in understanding the superconducting pairing symmetry. Here, we report definitive photoemission evidence of electron-spin exciton coupling in the iron-based superconductor CaKFe4As4, obtained via high-resolution ARPES. Our study identifies a distinct kink structure on the α band, observable only in the superconducting phase and closely linked with the superconductivity, indicative of strong electron-boson interactions. Notably, this kink structure corresponds to two distinct bosonic modes at 11 meV and 13 meV, aligning with spin resonance modes previously observed in inelastic neutron scattering experiments. This alignment underscores the significant role of antiferromagnetic fluctuations in the pairing mechanism of this superconductor. Furthermore, the unique momentum-dependent and orbital-selective properties of the coupling revealed by ARPES provide profound insights into the pairing symmetry, suggesting predominantly s_+- wave pairing facilitated by spin fluctuations. Our findings not only highlight the pivotal role of spin resonance in the superconductivity of CaKFe4As4 but also enhance understanding of the electron-spin exciton interactions in unconventional superconductors. △ Less

Submitted 5 March, 2025; originally announced March 2025.

Comments: Phys. Rev. X - Accepted 4 March, 2025

Uniaxial spin texture in a superconducting electron gas revealed by exchange interactions

Authors: Junyi Yang, Changjiang Liu, Xianjing Zhou, Hanyu Hou, Kaijun Yin, Jianguo Wen, John Pearson, Alexey Suslov, Dafei Jin, Jidong S. Jiang, Ulrich Welp, Jian-Min Zuo, Michael R. Norman, Anand Bhattacharya

Abstract: Two-dimensional superconductors with spin-textured Fermi surfaces can be a platform for realizing unconventional pairing states and are of substantial interest in the context of quantum information science, and superconducting spintronics/orbitronics. We observed an unusual in-plane uniaxial anisotropy in the superconducting 2D electron gas (2DEG) formed at EuOx/KTaO3 (110) interfaces, where the E… ▽ More Two-dimensional superconductors with spin-textured Fermi surfaces can be a platform for realizing unconventional pairing states and are of substantial interest in the context of quantum information science, and superconducting spintronics/orbitronics. We observed an unusual in-plane uniaxial anisotropy in the superconducting 2D electron gas (2DEG) formed at EuOx/KTaO3 (110) interfaces, where the EuOx is magnetic. This anisotropy is not evident in AlOx/KTaO3 (110) where the overlayer is non-magnetic. Our results are consistent with a highly anisotropic 'half-Rashba' spin-textured Fermi surface in 2DEGs formed at the KTaO3 (110) interface that is hidden from external magnetic fields due to a near cancellation between orbital and spin moments but revealed by exchange interactions of the electrons in the 2DEG with Eu moments near the EuOx/KTaO3 (110) interface. The interactions between the uniaxial spin texture and the magnetic overlayer offer new ways to explore the interplay between magnetism and 2D superconductivity. △ Less

Submitted 3 August, 2025; v1 submitted 26 February, 2025; originally announced February 2025.

Comments: Combined Manuscript (18 pages, 5 figures) and Supplemental Information (16 pages, 18 figures and 2 tables)

Exact quantum critical states with a superconducting quantum processor

Authors: Wenhui Huang, Xin-Chi Zhou, Libo Zhang, Jiawei Zhang, Yuxuan Zhou, Bing-Chen Yao, Zechen Guo, Peisheng Huang, Qixian Li, Yongqi Liang, Yiting Liu, Jiawei Qiu, Daxiong Sun, Xuandong Sun, Zilin Wang, Changrong Xie, Yuzhe Xiong, Xiaohan Yang, Jiajian Zhang, Zihao Zhang, Ji Chu, Weijie Guo, Ji Jiang, Xiayu Linpeng, Wenhui Ren , et al. (7 additional authors not shown)

Abstract: Anderson localization physics features three fundamental types of eigenstates: extended, localized, and critical. Confirming the presence of critical states necessitates either advancing the analysis to the thermodynamic limit or identifying a universal mechanism which can rigorously determine these states. Here we report the unambiguous experimental realization of critical states, governed by a r… ▽ More Anderson localization physics features three fundamental types of eigenstates: extended, localized, and critical. Confirming the presence of critical states necessitates either advancing the analysis to the thermodynamic limit or identifying a universal mechanism which can rigorously determine these states. Here we report the unambiguous experimental realization of critical states, governed by a rigorous mechanism for exact quantum critical states, and further observe a generalized mechanism that quasiperiodic zeros in hopping couplings protect the critical states. Leveraging a superconducting quantum processor with up to 56 qubits, we implement a programmable mosaic model with tunable couplings and on-site potentials. By measuring time-evolved observables, we identify both delocalized dynamics and incommensurately distributed zeros in the couplings, which are the defining features of the critical states. We map the localized-to-critical phase transition and demonstrate that critical states persist until quasiperiodic zeros are removed by strong long-range couplings, highlighting a novel generalized mechanism discovered in this experiment and shown with rigorous theory. Finally, we resolve the energy-dependent transition between localized and critical states, revealing the presence of anomalous mobility edges. △ Less

Submitted 25 March, 2025; v1 submitted 26 February, 2025; originally announced February 2025.

Comments: 6+29 pages, 4+14 figures. Discussions are updated

Stable Neel-Twisted Skyrmion Bags in a van der Waals Magnet Fe3-xGaTe2 at Room Temperature

Authors: Jialiang Jiang, Yaodong Wu, Lingyao Kong, Yongsen Zhang, Sheng Qiu, Huanhuan Zhang, Yajiao Ke, Shouguo Wang, Mingliang Tian, Jin Tang

Abstract: Magnetic skyrmion bags with diverse topological charges Q, offer prospects for future spintronic devices based on freedom of Q. While their emergence in van der Waals magnets holds the potential in developing Q-based 2D topological spintronics. However, previous room-temperature skyrmion bags necessitate special anisotropy engineering through disorder Fe intercalation, and the stable phase diagram… ▽ More Magnetic skyrmion bags with diverse topological charges Q, offer prospects for future spintronic devices based on freedom of Q. While their emergence in van der Waals magnets holds the potential in developing Q-based 2D topological spintronics. However, previous room-temperature skyrmion bags necessitate special anisotropy engineering through disorder Fe intercalation, and the stable phase diagram for skyrmion bags across room temperature regions is lacking. Here, we demonstrate the observation and electrical manipulation of room temperature skyrmion bags in Fe3-xGaTe2 without specially designed Fe intercalation. Combining the pulsed currents with the assistance of magnetic fields, skyrmion bags with various topological charges are generated and annihilated. Especially double nested skyrmion bags are also discovered at room temperature. The stable temperature-field diagram of skyrmion bags has been established. We also demonstrate the electrical-controlled topological phase transformations of skyrmion bags. Our results will provide novel insights for the design of 2D skyrmion-based high-performance devices. △ Less

Submitted 20 February, 2025; originally announced February 2025.

Comments: Published in Nano Letters DOI: 10.1021/acs.nanolett.4c06281

Anomalous Raman scattering in layered AgCrP$_2$Se$_6$: Helical modes and excitation energy-dependent intensities

Authors: Rahul Rao, Jie Jiang, Ruth Pachter, Thuc T. Mai, Valentine Mohaugen, Maria F. Muñoz, Ryan Siebenaller, Emmanuel Rowe, Ryan Selhorst, Andrea N. Giordano, Angela R. Hight Walker, Michael A. Susner

Abstract: Structural anisotropy in layered two-dimensional materials can lead to highly anisotropic optical absorption which, in turn, can profoundly a^ect their phonon modes. These e^ects include lattice orientation-dependent and excitation energy-dependent mode intensities that can enable new phononic and optoelectronic applications. Here, we report anomalous Raman spectra in single-crystalline AgCrP$_2$S… ▽ More Structural anisotropy in layered two-dimensional materials can lead to highly anisotropic optical absorption which, in turn, can profoundly a^ect their phonon modes. These e^ects include lattice orientation-dependent and excitation energy-dependent mode intensities that can enable new phononic and optoelectronic applications. Here, we report anomalous Raman spectra in single-crystalline AgCrP$_2$Se$_6$, a layered antiferromagnetic material. Density functional theory calculations and experimental measurements reveal several unique features in the Raman spectra of bulk and exfoliated AgCrP$_2$Se$_6$ crystals including three helical vibrational modes. These modes exhibit large Raman optical activities (circular intensity di^erences) in bulk AgCrP$_2$Se$_6$, which progressively decrease with thickness. We also observe strong excitation energy dependent peak intensities as well as a decrease in anti-Stokes peak intensities at room temperature with increasing excitation energy, resulting in an apparent cooling by up to 220 K. All of these anomalies in bulk and exfoliated flakes are attributed to the unique ABC layer stacking structure of AgCrP$_2$Se$_6$ and to the smaller unit cell volume that causes hybridization between the Se and Ag/Cr electron densities, resulting in charge transfer and strongly a^ecting the electron-phonon coupling. This work thus positions AgCrP$_2$Se$_6$ as an exciting new 2D material for optical and phononic applications. △ Less

Submitted 29 January, 2025; originally announced January 2025.

Comments: 22 pages, 6 figures

Overlay-aware Variation Study of Flip FET and Benchmark with CFET

Authors: Wanyue Peng, Haoran Lu, Jingru Jiang, Jiacheng Sun, Ming Li, Runsheng Wang, Heng Wu, Ru Huang

Abstract: In this work, we carried out an overlay-aware variation study on Flip FET (FFET) considering the impact on RC parasitics induced by the lithography misalignment in backside processes, and benchmarked it with CFET in terms of the power-performance (PP) and variation sources. The iso-leakage frequency degrades up to 2.20% with layout misalignment of 4 nm. It's found that the Drain Merge resistance d… ▽ More In this work, we carried out an overlay-aware variation study on Flip FET (FFET) considering the impact on RC parasitics induced by the lithography misalignment in backside processes, and benchmarked it with CFET in terms of the power-performance (PP) and variation sources. The iso-leakage frequency degrades up to 2.20% with layout misalignment of 4 nm. It's found that the Drain Merge resistance degrades significantly with misalignment increasing and is identified as the major variation source. Through careful DTCO with design rule optimization, the variation can be greatly suppressed, while the resistance fluctuation of the DM also drops substantially. Monte Carlo random experiments were also conducted, validating the variation reduction. Comparing with the CFET featuring self-aligned gate and much less overlay induced misalignment, fortunately, FFET's PP is still better except when misalignment reaches 8 nm, which is out of spec and nearly impossible. Considering the variabilities induced by the high aspect ratio processes, CFET still faces big challenges compared with FFET. △ Less

Submitted 27 January, 2025; originally announced January 2025.

Comments: Accepted by EDTM 2025

Journal ref: Proc. of EDTM 2025

Observation of liquid-solid transition of nanoconfined water at ambient temperature

Authors: Wentian Zheng, Shichen Zhang, Jian Jiang, Yipeng He, Rainer Stöhr, Andrej Denisenko, Jörg Wrachtrup, Xiao Cheng Zeng, Ke Bian, En-Ge Wang, Ying Jiang

Abstract: Nanoconfined water plays an indispensable role in various phenomena in biology, chemistry, and engineering. It exhibits many abnormal properties compared to bulk water, especially under strong confinement. However, the origin of those anomalies is still elusive due to the lack of structural information on hydrogen-bonding networks. Considering the inhomogeneity of the nanocavity and the tiny amoun… ▽ More Nanoconfined water plays an indispensable role in various phenomena in biology, chemistry, and engineering. It exhibits many abnormal properties compared to bulk water, especially under strong confinement. However, the origin of those anomalies is still elusive due to the lack of structural information on hydrogen-bonding networks. Considering the inhomogeneity of the nanocavity and the tiny amount of water molecules, conventional optical spectroscopies and nuclear magnetic resonance (NMR) fail to realize the structure analysis of nanoconfined water. Here, we addressed this issue by combining scanning probe microscopy (SPM) with advanced quantum sensing(QS) based on an atomic-size quantum sensor like nitrogen-vacancy (NV) center in diamond, which can apply the nanoscale-NMR for characterizing both the dynamics and structure of confined water at ambient conditions. We built a two-dimensional (2D) nanoconfined water system with a hexagonal-boron nitride (hBN) flake and a hydrophilic diamond surface. By using the SPM tip to measure the confinement size precisely, we observed a critical confinement size of ~2 nm, below which the water diffusion was significantly suppressed and the hydrogen-bonding network of water showed an ordered structure. Meanwhile, molecular dynamics (MD) simulation revealed a solid-like water contact layer on the diamond surface under strong confinement, which also reproduced the measured nanoscale-NMR spectra and confirmed the liquid-solid phase transition observed in the experiments. Notably, with this new SPM-QS platform, our results showed a promising way to elucidate the abnormal properties of nanoconfined water in future applications. △ Less

Submitted 19 December, 2024; originally announced December 2024.

Flexible and Efficient Semi-Empirical DFTB Parameters for Electronic Structure Prediction of 3D, 2D Iodide Perovskites and Heterostructures

Authors: Junke Jiang, Tammo van der Heide, Simon Thébaud, Carlos Raúl Lien-Medrano, Arnaud Fihey, Laurent Pedesseau, Claudio Quarti, Marios Zacharias, George Volonakis, Mikael Kepenekian, Bálint Aradi, Michael A. Sentef, Jacky Even, Claudine Katan

Abstract: Density Functional Tight-Binding (DFTB), an approximative approach derived from Density Functional Theory (DFT), has the potential to pave the way for simulations of large periodic or non-periodic systems. We have specifically tailored DFTB parameters to enhance the accuracy of electronic band gap calculations in both 3D and 2D lead-iodide perovskites, at a significantly reduced computational cost… ▽ More Density Functional Tight-Binding (DFTB), an approximative approach derived from Density Functional Theory (DFT), has the potential to pave the way for simulations of large periodic or non-periodic systems. We have specifically tailored DFTB parameters to enhance the accuracy of electronic band gap calculations in both 3D and 2D lead-iodide perovskites, at a significantly reduced computational cost relative to state-of-the-art ab initio calculations. Our electronic DFTB parameters allow computing not only the band gap but also effective masses of perovskite materials with reasonable accuracy compared to existing experimental data and state-of-the-art DFT calculations. The electronic band structures of vacancy-ordered and, lead- and iodide- deficient perovskites are also explored. Additionally, we demonstrate the efficiency of DFTB in computing electronic band alignments in perovskite heterostructures. The DFTB-based approach is anticipated to be beneficial for studying large-scale systems such as heterostructures and nanocrystals. △ Less

Submitted 19 January, 2025; v1 submitted 9 December, 2024; originally announced December 2024.

Comments: 44 pages, 9 figures

Hybrid skin-topological effect in non-Hermitian checkerboard lattices with large Chern numbers

Authors: Yi-Ling Zhang, Li-Wei Wang, Yang Liu, Zhao-Xian Chen, Jian-Hua Jiang

Abstract: Non-Hermitian topology provides a research frontier for exploring topological phenomena, revealing novel topological effects and driving the development of emergent materials and platforms. Here, we explore the non-Hermitian Chern insulator phases and the hybrid skin-topological effects in checkerboard lattices with synthetic gauge fluxes. Such lattices can be realized in integrated silicon photon… ▽ More Non-Hermitian topology provides a research frontier for exploring topological phenomena, revealing novel topological effects and driving the development of emergent materials and platforms. Here, we explore the non-Hermitian Chern insulator phases and the hybrid skin-topological effects in checkerboard lattices with synthetic gauge fluxes. Such lattices can be realized in integrated silicon photonic nanocircuits and microresonators as well as in arrays of evanescently coupled helical optical waveguides. With a simple and tunable design, the system is found to support non-Hermitian hybrid skin topological effects, exhibiting corner skin effects when the lattice symmetry either $C_4$ or $C_2$. An unconventional physical mechanism is revealed as the origin of such a transition which is connected to the corner-induced scattering between the multiple chiral edge channels. These properties are enabled by the large Chern number and the rich non-Hermitian topological edge states in our system, revealing the diverse non-Hermitian topological bulk-boundary correspondence. Our design offers excellent controllability and experimental feasibility, making it appealing for studying non-Hermitian topological phenomena. △ Less

Submitted 11 November, 2024; originally announced November 2024.

Manipulating ferroelectric topological polar structures with twisted light

Authors: Nimish Nazirkar, Viet Tran, Pascal Bassene, Atoumane Ndiaye, Julie Barringer, Jie Jiang, Wonsuk Cha, Ross Harder, Jian Shi, Moussa NGom, Edwin Fohtung

Abstract: The dynamic control of novel states of matter beyond thermodynamic equilibrium is a fundamental pursuit in condensed matter physics. Intense terahertz fields have enabled metal-insulator transitions, superconductivity, quantum paraelectric ferroelectricity, and room-temperature magnetization via circularly polarized terahertz electric fields. These effects hinge on the excitation of infrared-activ… ▽ More The dynamic control of novel states of matter beyond thermodynamic equilibrium is a fundamental pursuit in condensed matter physics. Intense terahertz fields have enabled metal-insulator transitions, superconductivity, quantum paraelectric ferroelectricity, and room-temperature magnetization via circularly polarized terahertz electric fields. These effects hinge on the excitation of infrared-active soft phonon modes by terahertz fields. Expanding this concept, recent theory suggests that ferroelectric polarization may be manipulated through terahertz twisted light, transferring orbital angular momentum to create ferroelectric skyrmions. Our study experimentally demonstrates that such control is possible in quasi-2D ferroelectric CsBiNb2O7 using twisted UV light with orbital angular momentum (OAM). By resonantly exciting both the ferroelectric mode and the octahedral tilting mode, twisted UV light dynamically modulates the ferroelectric polarization. We employ in-situ X-ray Bragg coherent diffractive imaging, twisted optical Raman spectroscopy, and density functional theory to three-dimensionally resolve ionic displacement fields and polarization texture changes. Our observations reveal deterministic, reversible twisted light-induced strain and ionic displacements within the unit cell, causing substantial microscopic polarization changes. This interaction between twisted photons, phonon modes, and induced ionic displacements breaks symmetry and stabilizes a non-equilibrium ferroelectric phase with topological solitons. These findings offer a new path to control ferroelectricity and magnetism, opening avenues for novel optoelectronic devices such as ultrafast non-volatile memory switches by using light to coherently control ferroic states. △ Less

Submitted 27 October, 2024; originally announced October 2024.

Comments: 14 pages, 5 figures

Mechanics of soft-body rolling motion without external torque

Authors: Xudong Liang, Yimiao Ding, Zihao Yuan, Junqi Jiang, Zongling Xie, Peng Fei, Yixuan Sun, Guoying Gu, Zheng Zhong, Feifei Chen, Guangwei Si, Zhefeng Gong

Abstract: The Drosophila larva, a soft-body animal, can bend its body and roll efficiently to escape danger. However, contrary to common belief, this rolling motion is not driven by the imbalance of gravity and ground reaction forces. Through functional imaging and ablation experiments, we demonstrate that the sequential actuation of axial muscles within an appropriate range of angles is critical for genera… ▽ More The Drosophila larva, a soft-body animal, can bend its body and roll efficiently to escape danger. However, contrary to common belief, this rolling motion is not driven by the imbalance of gravity and ground reaction forces. Through functional imaging and ablation experiments, we demonstrate that the sequential actuation of axial muscles within an appropriate range of angles is critical for generating rolling. We model the interplay between muscle contraction, hydrostatic skeleton deformation, and body-environment interactions, and systematically explain how sequential muscle actuation generates the rolling motion. Additionally, we constructed a pneumatic soft robot to mimic the larval rolling strategy, successfully validating our model. This mechanics model of soft-body rolling motion not only advances the study of related neural circuits, but also holds potential for applications in soft robotics. △ Less

Submitted 10 October, 2024; originally announced October 2024.

Revealing nanoscale structural phase separation in La$_{3}$Ni$_{2}$O$_{7-δ}$ single crystal via scanning near-field optical microscopy

Authors: Xiaoxiang Zhou, Weihong He, Kaipeng Ni, Mengwu Huo, Deyuan Hu, Yinghao Zhu, Enkang Zhang, Zhicheng Jiang, Shuaikang Zhang, Shiwu Su, Juan Jiang, Yajun Yan, Yilin Wang, Dawei Shen, Xue Liu, Jun Zhao, Meng Wang, Zengyi Du, Donglai Feng

Abstract: The discovery of superconductivity in La3Ni2O7-$δ$ under high pressure,with an onset critical temperature around 80 K, has sparked significant interest in the superconducting phases of Ruddlesden-Popper nickelates, Lan+1NinO3n+1. While La4Ni3O10 exhibits nearly 100% superconductivity with Tc~30 K under high pressure, magnetic susceptibility studies on La3Ni2O7-$δ$, however, reveal a more complex p… ▽ More The discovery of superconductivity in La3Ni2O7-$δ$ under high pressure,with an onset critical temperature around 80 K, has sparked significant interest in the superconducting phases of Ruddlesden-Popper nickelates, Lan+1NinO3n+1. While La4Ni3O10 exhibits nearly 100% superconductivity with Tc~30 K under high pressure, magnetic susceptibility studies on La3Ni2O7-$δ$, however, reveal a more complex picture, indicating either filamentary superconductivity or that approximately 50% of crystal phase becomes superconducting in polycrystalline samples. In this study, we employed scattering-type scanning near-field optical microscopy to visualize nanoscale structural phase separation in La3Ni2O7-$δ$, identifying enhanced optical conductivity with stripes approximately 183 nm wide. These stripes run diagonally with respect to the Ni-O-Ni bond directions in the a-b plane, ruling out the possibility that they arise from impurity phases, like the '1313', '214' or '4310' structures. The dark regions and bright stripes exhibit optical conductivities ~ 22% and 29% of gold's, respectively. Additionally, we find that the bright stripes constitute about 38% of the total field of view, while the remainder consists of dark regions and the transitional region between dark regions and bright stripes. Our results suggest that optical conductivity stripes originate from nanoscale structural phase separation. In contrast, La4Ni3O10 exhibits uniform and higher optical conductivity with no observable evidence of phase separation. Thus, our study represents a pioneering effort to directly image nanoscale phase separation in Lan+1NinO3n+1 nickelates. This observation could provide crucial insights into the factors that limit the superconducting volume fraction of La3Ni2O7-$δ$, highlighting SNOM as a powerful probe for exploring nanoscale low-energy physics in correlated quantum materials. △ Less

Submitted 17 March, 2025; v1 submitted 9 October, 2024; originally announced October 2024.

Comments: 12 pages, 4 figures

Electric imaging and dynamics of photo-charged graphene edge

Authors: Zhe Ding, Zhousheng Chen, Xiaodong Fan, Weihui Zhang, Jun Fu, Yumeng Sun, Zhi Cheng, Zhiwei Yu, Kai Yang, Yuxin Li, Xing Liu, Pengfei Wang, Ya Wang, Jianhua Jiang, Hualing Zeng, Changgan Zeng, Guosheng Shi, Fazhan Shi, Jiangfeng Du

Abstract: The one-dimensional side gate based on graphene edges shows a significant capability of reducing the channel length of field-effect transistors, further increasing the integration density of semiconductor devices. The nano-scale electric field distribution near the edge provides the physical limit of the effective channel length, however, its imaging under ambient conditions still lacks, which is… ▽ More The one-dimensional side gate based on graphene edges shows a significant capability of reducing the channel length of field-effect transistors, further increasing the integration density of semiconductor devices. The nano-scale electric field distribution near the edge provides the physical limit of the effective channel length, however, its imaging under ambient conditions still lacks, which is a critical aspect for the practical deployment of semiconductor devices. Here, we used scanning nitrogen-vacancy microscopy to investigate the electric field distribution near edges of a single-layer-graphene. Real-space scanning maps of photo-charged floating graphene flakes were acquired with a spatial resolution of $\sim$ 10 nm, and the electric edge effect was quantitatively studied by analyzing the NV spin energy level shifts due to the electric Stark effect. Since the graphene flakes are isolated from external electric sources, we brought out a theory based on photo-thermionic effect to explain the charge transfer from graphene to oxygen-terminated diamond probe with a disordered distribution of charge traps. Real-time tracing of electric fields detected the photo-thermionic emission process and the recombination process of the emitted electrons. This study provides a new perspective for graphene-based one-dimensional gates and opto-electronics with nanoscale real-space imaging, and moreover, offers a novel method to tune the chemical environment of diamond surfaces based on optical charge transfer. △ Less

Submitted 23 September, 2024; originally announced September 2024.

Comments: 8 pages, 4 figures

Tunable Anomalous Hall Effect in a Kagome Ferromagnetic Weyl Semimetal

Authors: Samuel E. Pate, Bin Wang, Yang Zhang, Bing Shen, Enke Liu, Ivar Martin, J. Samuel Jiang, Xiuquan Zhou, Duck Young Chung, Mercouri G. Kanatzidis, Ulrich Welp, Wai-Kwong Kwok, Zhi-Li Xiao

Abstract: Emerging from the intricate interplay of topology and magnetism, the giant anomalous Hall effect (AHE) is the most known topological property of the recently discovered kagome ferromagnetic Weyl semimetal Co_3Sn_2S_2 with the magnetic Co atoms arranged on a kagome lattice. Here we report that the AHE in Co_3Sn_2S_2 can be fine-tuned by an applied magnetic field orientated within ~2 degrees of the… ▽ More Emerging from the intricate interplay of topology and magnetism, the giant anomalous Hall effect (AHE) is the most known topological property of the recently discovered kagome ferromagnetic Weyl semimetal Co_3Sn_2S_2 with the magnetic Co atoms arranged on a kagome lattice. Here we report that the AHE in Co_3Sn_2S_2 can be fine-tuned by an applied magnetic field orientated within ~2 degrees of the kagome plane, while beyond this regime, it stays unchanged. Particularly, it can vanish in magnetic fields parallel to the kagome plane and even decrease in magnetic fields collinear with the spin direction. This tunable AHE can be attributed to local spin switching enabled by the geometrical frustration of the magnetic kagome lattice, revealing that spins in a kagome ferromagnet change their switching behavior as the magnetic field approaches the kagome plane. Our results also suggest a versatile way to tune the properties of a kagome magnet. △ Less

Submitted 20 September, 2024; originally announced September 2024.

Journal ref: Adv. Sci. 11, 2406882 (2024)