https://iopscience.iop.org/journal/rss/0953-8984 Latest articles for Journal of Physics: Condensed Matter https://iopscience.iop.org/image/iopscience-rss.gif https://iopscience.iop.org/journal/rss/0953-8984 https://iopscience.iop.org/article/10.1088/1361-648X/ae95ca This work develops an analytical model for quantitatively estimating the Urbach energy as a function of doping concentration in semiconductors with non-isovalent doping, accounting contributions from structural disorder, carrier-impurity interactions, and carrier–phonon interactions. In the first part of the paper, the contribution from carrier-impurity interaction is formulated as per the Halperin–Lax and Edwards model, the correction term due to structural disorder is included, and the carrier–phonon interaction contribution is formulated by analytically solving the correlation function for longitudinal-optical phonon–carrier interactions. The total is expressed separately for n-type and p-type impurities, and the calculated values agree very well with the experimental data available in the literature for Group III–V semiconductors at 300 K. We further quantify the relative scaling of individual contributions with doping concentration at 300 K. Dibya Prakash Kar and Pankaj R Sagdeo 2026-08-20T23:00:00Z Journal of Physics: Condensed Matter Dibya Prakash Kar and Pankaj R Sagdeo Dibya Prakash Kar and Pankaj R Sagdeo 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335702 https://iopscience.iop.org/article/10.1088/1361-648X/ae95ca/pdf 21/August/2026 33 38 Journal of Physics: Condensed Matter 335702 10.1088/1361-648X/ae95ca https://iopscience.iop.org/article/10.1088/1361-648X/ae97a9 Flat-band lattices support compact localized states with sublattice-selective amplitude patterns, but it is less clear whether this geometry can protect nearby boundary resonances from disorder-induced leakage into the bulk. Here we identify a matrix-element selection rule for sublattice-selective leakage suppression in a gyroscopic Lieb mechanical lattice. The lattice hosts a nearly -sublattice-dark quasi-flat band and a boundary resonance in the adjacent low-density spectral window. Under sublattice-resolved onsite disorder averaged over 48 realizations with bootstrap 95% confidence intervals, the small- leakage prefactors obey (CI ) for ; a full-range quartic fit and a fit-free integrated disorder response give more conservative ratios of and , respectively. Bond-stiffness disorder shows a matching bond-resolved selectivity with near-perfect variance additivity ( ), confirming that the mechanism is not tied to onsite disorder. A Fermi-golden-rule analysis on the strip eigenmodes attributes the asymmetry to a suppressed matrix element whose isotropic scalar-site overlap-density evaluation supports the observed order-of-magnitude asymmetry (details in section 4.3). The selection rule remains present under spring anisotropy at every anisotropy where the perturbative fit converges above the twelve-realization ensemble noise floor. The mechanism is geometric rather than topological and provides a route to reducing selected bulk-leakage channels in multi-sublattice mechanical, phononic and photonic flat-band platforms. Dongwook Lee and Jiwon Seo 2026-08-20T23:00:00Z Journal of Physics: Condensed Matter Dongwook Lee and Jiwon Seo Dongwook Lee and Jiwon Seo 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335401 https://iopscience.iop.org/article/10.1088/1361-648X/ae97a9/pdf 21/August/2026 33 38 Journal of Physics: Condensed Matter 335401 10.1088/1361-648X/ae97a9 https://iopscience.iop.org/article/10.1088/1361-648X/ae9663 We investigate the zero-temperature magnon spectra of collinear multi-sublattice magnetic systems using the Holstein–Primakoff formalism. We model the itinerant magnetism from first principles by utilizing exchange parameters derived from density functional theory. The developed theoretical framework—which yields expressions for the magnon dynamical matrix, group velocity and spin-wave stiffness—is then applied to three distinct Heusler compounds: the ferrimagnet Mn CoAl, the ferromagnet Co MnSi, and the fully compensated ferrimagnet Mn LiAl. By successfully capturing behaviors ranging from standard parabolic ferromagnetic dispersions to complex linear antiferromagnetic dynamics, the present formalism provides a systematic framework for evaluating spin-wave parameters. Tariq Hadji 2026-08-18T23:00:00Z Journal of Physics: Condensed Matter Tariq Hadji Tariq Hadji 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335805 https://iopscience.iop.org/article/10.1088/1361-648X/ae9663/pdf 19/August/2026 33 38 Journal of Physics: Condensed Matter 335805 10.1088/1361-648X/ae9663 https://iopscience.iop.org/article/10.1088/1361-648X/ae9706 We study the nearest-neighbor spin-ice model subjected to a magnetic field applied along the global [111] and [110] directions, focusing on the role of sample geometry in stabilizing topological phase transitions. While no Kasteleyn transition is expected for this field orientations in the thermodynamic limit, we show that constraining the transverse dimensions of the system qualitatively changes the behavior. For samples elongated along the field direction with finite transverse area, the divergence-free constraint quantizes the number of string excitations that can span the system. As a result, the magnetization evolves through a cascade of discrete transitions corresponding to the successive entry of individual strings. Using Monte Carlo simulations, we demonstrate that each transition is marked by sharp magnetization steps and peaks in the specific heat and susceptibility, whose amplitudes scale linearly with the system length. We complement the numerical results with an analytical treatment based on the entropy-energy balance on a system with reduced dimensionality, deriving the critical fields associated with each topological sector. In the isotropic limit these transitions merge into a smooth crossover, but for anisotropic samples they remain sharply resolved, illustrating an unconventional mechanism by which finite geometry stabilizes topological phase transitions in frustrated magnets. R A Borzi, E S Loscar and S A Grigera 2026-08-18T23:00:00Z Journal of Physics: Condensed Matter R A Borzi <em>et al</em> R A Borzi <em>et al</em> 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335804 https://iopscience.iop.org/article/10.1088/1361-648X/ae9706/pdf 19/August/2026 33 38 Journal of Physics: Condensed Matter 335804 10.1088/1361-648X/ae9706 https://iopscience.iop.org/article/10.1088/1361-648X/ae9707 The pursuit of new two-dimensional (2D) carbon allotropes with semiconducting characteristics has long been a focal point in the field of materials science. In this study, a novel 2D carbon allotrope with an intrinsic semiconducting nature has been theoretically proposed within first-principles approach. This new 2D carbon allotrope possesses a puckered carbon framework with mixed sp2+ sp3 hybridization, referred to as puckered C18-carbon. Its superior structural stability is strongly supported by the calculations of cohesive energy, phonon dispersion, and elastic constants, in addition to ab initio molecular dynamics simulations at temperatures up to 800 K. Furthermore, the associated mechanical, electronic, and optical response properties of the new carbon phase have been systematically revealed in this study. Notably, this puckered carbon sheet exhibits semiconducting behaviors, featuring a wide direct band gap that can be further modulated by applying biaxial strain. The appealing features of the proposed new 2D carbon phase, including its superior structural stability, high mechanical strength, direct semiconductor characteristics, along with an extraordinary optical response in the blue and ultraviolet regime, render it a promising candidate for use in future carbon nanoelectronic, optoelectronic, photovoltaic, and visible-light emitting devices. Wentao Li, Zhehao Li, Qiling Zhou and Zhuorui Lin 2026-08-18T23:00:00Z Journal of Physics: Condensed Matter Wentao Li <em>et al</em> Wentao Li <em>et al</em> 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335501 https://iopscience.iop.org/article/10.1088/1361-648X/ae9707/pdf 19/August/2026 33 38 Journal of Physics: Condensed Matter 335501 10.1088/1361-648X/ae9707 https://iopscience.iop.org/article/10.1088/1361-648X/ae9024 We report a combined experimental and theoretical investigation of the spin dynamics in the very hard 3d–4f single-molecule magnet (SMM) {Cr3Dy3}, where a central fluorido bridge (µ3–F−) suppresses zero-field quantum tunneling of magnetization (QTM). Utilizing inelastic neutron scattering, heat capacity and ac susceptibility techniques, we have probed the low-lying magnetic excitations and their response to applied magnetic fields in polycrystalline samples. Full ab initio calculations, incorporating the experimental data, have provided an unambiguous determination of the ferromagnetic Dy–Dy coupling (JDy–Dy = 0.016 meV) mediated by the µ3–F− bridge and antiferromagnetic Cr–Dy interactions (JCr–Dy = − 0.215 meV). The significant energy gap between the ferrimagnetic ground state and the lowest exchange-induced excited state (1.03 meV) provides a direct mechanistic basis for the suppression of QTM, leading to its exceptional SMM property. Shuixian Qu, Yuan-Qi Zhai, J Ross Stewart, Xinzhi Liu, Bo-Kai Ling, Hanjie Guo, Yan-Zhen Zheng, Jinkui Zhao and Zhendong Fu 2026-08-17T23:00:00Z Journal of Physics: Condensed Matter Shuixian Qu <em>et al</em> Shuixian Qu <em>et al</em> 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335803 https://iopscience.iop.org/article/10.1088/1361-648X/ae9024/pdf 18/August/2026 33 38 Journal of Physics: Condensed Matter 335803 10.1088/1361-648X/ae9024 https://iopscience.iop.org/article/10.1088/1361-648X/ae943f Demonstration of non-Abelian statistics of Majorana bound states (MBS) is crucial for the realization of fault-tolerant topological quantum computation. Two-dimensional platforms such as planar Josephson junction (PJJ) require an in-plane magnetic field to generate a pair of MBS at its non-superconducting channel ends; however, the fixed direction of the in-plane magnetic field puts a constraint on the realization of a multi-terminal topological planar junction, and hence its ability to physically move multiple MBS—which is necessary for performing the fusion and braiding operations. Here we show that in a PJJ coupled to a Skyrmion crystal, which can generate multiple pairs of MBS in the absence of any external magnetic field, the non-trivial fusion and braiding operations can be performed. Our numerical calculations, designed for realistic two-dimensional quantum systems, certify the feasibility of experimental realization of the proposed device schemes. We find that both -wave and -wave superconducting leads can generate the MBS; indicating that the MBS movement operations can be performed at higher temperatures using -wave superconducting leads. Our results establish that the Skyrmion crystal-coupled PJJ is a viable platform for the generation and controlled movement of the MBS. Pankaj Sharma and Narayan Mohanta 2026-08-17T23:00:00Z Journal of Physics: Condensed Matter Pankaj Sharma and Narayan Mohanta Pankaj Sharma and Narayan Mohanta 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335302 https://iopscience.iop.org/article/10.1088/1361-648X/ae943f/pdf 18/August/2026 33 38 Journal of Physics: Condensed Matter 335302 10.1088/1361-648X/ae943f https://iopscience.iop.org/article/10.1088/1361-648X/ae94ce Rich physical phenomena arise at novel magnetic topological surfaces and interfaces, which have become a highly pursued forefront for quantum science and technology. Major breakthroughs have been propelled by ever improving capabilities of realizing and manipulating, at the atomic level, unprecedented quantum behavior when emerging magnetic order, tunable spin–orbit coupling and topologically nontrivial states cooperate. In this review, we focus on interface-modulated magnetism in tetradymite-based magnetic topological insulators and semimetals. We highlight nontrivial spin textures and dynamics that are enabled by synergy of complex crystalline phases, competing orders, engineered defects and symmetry breaking. We envision deeper understanding of interfacially coupled magnetism and topology to further boost fundamental discoveries and technological breakthroughs. Vikas Saini and Hang Chi 2026-08-17T23:00:00Z Journal of Physics: Condensed Matter Vikas Saini and Hang Chi Vikas Saini and Hang Chi 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 333003 https://iopscience.iop.org/article/10.1088/1361-648X/ae94ce/pdf 18/August/2026 33 38 Journal of Physics: Condensed Matter 333003 10.1088/1361-648X/ae94ce https://iopscience.iop.org/article/10.1088/1361-648X/ae95cd The effects of short-range ordered and disordered correlation on electronic transport in Fibonacci graphene superlattices with modulated Fermi velocity were analyzed. Ordered and disordered correlation is introduced through the Fibonacci sequence, modified using both correlated and random approaches, generating distinct structural configurations with position-dependent variations in Fermi velocity. Charge carriers are modeled as relativistic quantum particles within an effective low-energy Hamiltonian, and transport properties are analyzed using the transfer matrix method and the Landauer–Büttiker formalism. The results show that ordered aperiodic systems with modulated Fermi velocities exhibit different transport regimes depending on structural correlation and the type of seed used. As the Fibonacci generation increases, the system stabilizes due to the rise in double barriers, which directly impacts transport properties. In certain energy ranges, Fibonacci structures even outperform periodic ones, highlighting the role of short-range ordered and disordered correlations. F J García-Rodríguez, H García-Cervantes, Gerardo J Escalera Santos, R Rodríguez-González and I Rodríguez-Vargas 2026-08-17T23:00:00Z Journal of Physics: Condensed Matter F J García-Rodríguez <em>et al</em> F J García-Rodríguez <em>et al</em> 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 335301 https://iopscience.iop.org/article/10.1088/1361-648X/ae95cd/pdf 18/August/2026 33 38 Journal of Physics: Condensed Matter 335301 10.1088/1361-648X/ae95cd https://iopscience.iop.org/article/10.1088/1361-648X/ae8b4d Amorphous silicon nitride ( -Si N ) is widely used as the charge storage layer of charge-trap flash (CTF) memory devices, where its high density of deep localized electronic states enables long-term data retention at room temperature. Despite its technological relevance, the microscopic nature of the charge traps in -Si N is still controversial. In recent years, atomistic modeling has enabled the characterization of intrinsic defects in , providing new insights into their structural and electronic properties that are comprehensively discussed in this review. We demonstrate that a variety of structural irregularities, including over- and undercoordinated atoms, bonds, vacancies and strained bonds, introduce localized electronic states in the amorphous network, which act as precursor sites for trapping and retaining electrons. The associated charge transition processes at these trapping sites are analyzed within the framework of nonradiative multiphonon theory and evaluated in the context of macroscopic CTF functionality. Additionally, we present a density functional theory-based computational approach to estimate electron capture cross sections of intrinsic defect sites in . Christoph Wilhelmer, Lukas Hückmann, Jonathon Cottom, Dominic Waldhoer, Jörg Meyer and Tibor Grasser 2026-08-16T23:00:00Z Journal of Physics: Condensed Matter Christoph Wilhelmer <em>et al</em> Christoph Wilhelmer <em>et al</em> 2026 <em>Journal of Physics: Condensed Matter</em> <b>38</b> 333002 https://iopscience.iop.org/article/10.1088/1361-648X/ae8b4d/pdf 17/August/2026 33 38 Journal of Physics: Condensed Matter 333002 10.1088/1361-648X/ae8b4d