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Anti-Sisyphus driving in a matter-wave swing
Authors:
Wen L. Liu,
Jun Jian,
Ning X. Zheng,
Hui Tang,
Ji Z. Wu,
Yu Q. Li,
Wen X. Zhang,
Jie Ma,
Suo T. Jia
Abstract:
Dilute-gas Bose-Einstein condensates are an exceptionally versatile testbed for the investigation of physics phenomenon especially the well-known classical system. Here we use a degenerate Bose gas of sodium atoms confined in an optical dipole trap to simulate the matter-wave on the swing. Under the driving of Anti-Sisyphus process, the swing was excited successfully. Moreover, the spin echo like…
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Dilute-gas Bose-Einstein condensates are an exceptionally versatile testbed for the investigation of physics phenomenon especially the well-known classical system. Here we use a degenerate Bose gas of sodium atoms confined in an optical dipole trap to simulate the matter-wave on the swing. Under the driving of Anti-Sisyphus process, the swing was excited successfully. Moreover, the spin echo like behavior and collective-mode excitation appear during the oscillation of matter-wave swing, manifesting the quantum nature of the system beyond its classical counterpart. Our work lays the foundation for matter-wave on the swing and more generally points to a future of practical applications for the motional quantum states linked with quantum information science.
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Submitted 19 June, 2025;
originally announced June 2025.
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Spontaneous ferromagnetism induced topological phase transition in EuB6
Authors:
W. L. Liu,
X. Zhang,
S. M. Nie,
Z. T. Liu,
X. Y. Sun,
H. Y. Wang,
J. Y. Ding,
L. Sun,
Z. Huang,
H. Su,
Y. C. Yang,
Z. C. Jiang,
X. L. Lu,
J. S. Liu,
Z. H. Liu,
S. L. Zhang,
H. M. Weng,
Y. F. Guo,
Z. J. Wang,
D. W. Shen,
Z. Liu
Abstract:
The interplay between various symmetries and electronic bands topology is one of the core issues for topological quantum materials. Spontaneous magnetism, which leads to the breaking of time-reversal symmetry, has been proven to be a powerful approach to trigger various exotic topological phases. In this work, utilizing the combination of angle-resolved photoemission spectroscopy, magneto-optical…
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The interplay between various symmetries and electronic bands topology is one of the core issues for topological quantum materials. Spontaneous magnetism, which leads to the breaking of time-reversal symmetry, has been proven to be a powerful approach to trigger various exotic topological phases. In this work, utilizing the combination of angle-resolved photoemission spectroscopy, magneto-optical Kerr effect microscopy and first-principles calculations, we present the direct evidence on the realization of the long-sought spontaneous time-reversal symmetry breaking induced topological phase transition in soft ferromagnetic EuB$_6$. We successfully disentangle the bulk band structure from complicated surface states, and reveal the hallmark band inversion occurring between two opposite-parity bulk bands below the phase transition temperature. Besides, our magneto-optical Kerr effect microscopy result confirms the simultaneous formation of magnetic domains in EuB$_6$, implying the intimate link between the topological phase transition and broken time-reversal symmetry therein. Our results demonstrate that EuB$_6$ provides a potential platform to study the interplay between the topological phases and tunable magnetic orders.
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Submitted 8 March, 2021;
originally announced March 2021.
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Electronic structure of the high-mobility two-dimensional antiferromagnetic metal GdTe$_3$
Authors:
J. S. Liu,
S. C. Huan,
Z. H. Liu,
W. L. Liu,
Z. T. Liu,
X. L. Lu,
Z. Huang,
Z. C. Jiang,
X. Wang,
N. Yu,
Z. Q. Zou,
Y. F. Guo,
D. W. Shen
Abstract:
The new-found two-dimensional antiferromagnetic GdTe$_3$ is attractive owing to its highest carrier mobility among all known layered magnetic materials, as well as its potential application for novel magnetic twistronic and spintronic devices. Here, we have used high-resolution angle-resolved photoemission spectroscopy to investigate its Fermi surface topology and low-lying electronic band structu…
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The new-found two-dimensional antiferromagnetic GdTe$_3$ is attractive owing to its highest carrier mobility among all known layered magnetic materials, as well as its potential application for novel magnetic twistronic and spintronic devices. Here, we have used high-resolution angle-resolved photoemission spectroscopy to investigate its Fermi surface topology and low-lying electronic band structure. The Fermi surface is partially gapped by charge density wave below the transition temperature, the residual part reconstructs making GdTe$_3$ metallic. The high carrier mobility can be attributed to the sharp and nearly linear band dispersions near the Fermi energy. We find that the scattering rate of the linear band near the Fermi energy is almost linear within a wide energy range, indicating that GdTe$_3$ is a non-Fermi liquid metal. Our results in this paper provide a fundamental understanding of this layered Van der Waals antiferromagnetic materials to guide future studies on it.
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Submitted 26 October, 2020;
originally announced October 2020.
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Dual topological superconducting states in the layered titanium-based oxypnictide superconductor BaTi$_2$Sb$_2$O
Authors:
Z. Huang,
W. L. Liu,
H. Y. Wang,
Y. L. Su,
Z. T. Liu,
X. B. Shi,
S. Y. Gao,
Z. C. Jiang,
Z. H. Liu,
J. S. Liu,
X. L. Lu,
Y. C. Yang,
J. X. Zhang,
S. C. Huan,
W. Xia,
J. H. Wang,
Y. S. Wu,
X. Wang,
N. Yu,
Y. B. Huang,
S. Qiao,
J. Li,
W. W. Zhao,
Y. F. Guo,
G. Li
, et al. (1 additional authors not shown)
Abstract:
Topological superconductors have long been predicted to host Majorana zero modes which obey non-Abelian statistics and have potential for realizing non-decoherence topological quantum computation. However, material realization of topological superconductors is still a challenge in condensed matter physics. Utilizing high-resolution angle-resolved photoemission spectroscopy and first-principles cal…
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Topological superconductors have long been predicted to host Majorana zero modes which obey non-Abelian statistics and have potential for realizing non-decoherence topological quantum computation. However, material realization of topological superconductors is still a challenge in condensed matter physics. Utilizing high-resolution angle-resolved photoemission spectroscopy and first-principles calculations, we predict and then unveil the coexistence of topological Dirac semimetal and topological insulator states in the vicinity of Fermi energy ($E_F$) in the titanium-based oxypnictide superconductor BaTi$_2$Sb$_2$O. Further spin-resolved measurements confirm its spin-helical surface states around $E_F$, which are topologically protected and give an opportunity for realization of Majorana zero modes and Majorana flat bands in one material. Hosting dual topological superconducting states, the intrinsic superconductor BaTi$_2$Sb$_2$O is expected to be a promising platform for further investigation of topological superconductivity.
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Submitted 14 September, 2020;
originally announced September 2020.
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Photoemission Spectroscopic Evidence for the Dirac Nodal Line in Monoclinic Semimetal SrAs$_3$
Authors:
Y. K. Song,
G. W. Wang,
S. C. Li,
W. L. Liu,
X. L. Lu,
Z. T. Liu,
Z. J. Li,
J. S. Wen,
Z. P. Yin,
Z. H. Liu,
D. W. Shen
Abstract:
Topological nodal-line semimetals with exotic quantum properties are characterized by symmetry-protected line-contact bulk band crossings in the momentum space. However, in most of identified topological nodal-line compounds, these topological non-trivial nodal lines are enclosed by complicated topological trivial states at the Fermi energy ($E_F$), which would perplex their identification and hin…
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Topological nodal-line semimetals with exotic quantum properties are characterized by symmetry-protected line-contact bulk band crossings in the momentum space. However, in most of identified topological nodal-line compounds, these topological non-trivial nodal lines are enclosed by complicated topological trivial states at the Fermi energy ($E_F$), which would perplex their identification and hinder further applications. Utilizing angle-resolved photoemission spectroscopy and first-principles calculations, we provide compelling evidence for the existence of Dirac nodal-line fermions in the monoclinic semimetal SrAs$_3$, which are close to $E_F$ and away from distraction of complex trivial Fermi surfaces or surface states. Our calculation indicates that two bands with opposite parity are inverted around \emph{Y} near $E_F$, which results in the single nodal loop at the $Γ$-\emph{Y}-\emph{S} plane with a negligible spin-orbit coupling effect. We track these band crossings and then unambiguously identify the complete nodal loop quantitatively, which provides a critical experimental support to the prediction of nodal-line fermions in the CaP$_3$ family of materials. Hosting simple topological non-trivial bulk electronic states around $E_F$ and no interfering with surface states on the natural cleavage plane, SrAs$_3$ is expected to be a potential platform for topological quantum state investigation and applications.
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Submitted 27 August, 2019;
originally announced September 2019.
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Effect of aging-induced disorder on the quantum transport properties of atomically thin WTe$_{2}$
Authors:
W. L. Liu,
M. L. Chen,
X. X. Li,
S. Dubey,
T. Xiong,
Z. M. Dai,
J. Yin,
W. L. Guo,
J. L. Ma,
Y. N. Chen,
J. Tan,
D. Li,
Z. H. Wang,
W. Li,
V. Bouchiat,
D. M. Sun,
Z. Han,
Z. D. Zhang
Abstract:
Atomically thin layers of transition-metal dicalcogenides (TMDCs) are often known to be metastable in the ambient atmosphere. Understanding the mechanism of degradation is essential for their future applications in nanoelectronics, and thus has attracted intensive interest recently. Here, we demonstrate a systematic study of atomically thin WTe$_{2}$ in its low temperature quantum electronic trans…
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Atomically thin layers of transition-metal dicalcogenides (TMDCs) are often known to be metastable in the ambient atmosphere. Understanding the mechanism of degradation is essential for their future applications in nanoelectronics, and thus has attracted intensive interest recently. Here, we demonstrate a systematic study of atomically thin WTe$_{2}$ in its low temperature quantum electronic transport properties. Strikingly, while the temperature dependence of few layered WTe$_{2}$ showed clear metallic tendency in the fresh state, degraded devices first exhibited a re-entrant insulating behavior, and finally entered a fully insulating state. Correspondingly, a crossover from parabolic to linear magnetoresistance, and finally to weak anti-localization was seen. Real-time Raman scattering measurement, together with transmission electron microscopy studies done before and after air degradation of atomically thin WTe$_{2}$ further confirmed that the material gradually form amorphous islands. It thus leads to localized electronic states and explains the low temperature Coulomb gap observed in transport measurements. Our study reveals for the first time the correlation between the unusual magnetotransport and disorder in few-layered WTe$_{2}$, which is indispensable in providing guidance on its future devices application.
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Submitted 16 August, 2016;
originally announced August 2016.