Article
Physics, Condensed Matter
Liangzhong Lin, Jiaji Zhu, Dong Zhang, Zhenhua Wu
Summary: In this study, we theoretically investigate the electron transport through a single-barrier structure in HgTe/CdTe quantum wells with inverted band structure. The transmission probabilities show significant dependence on various factors, including the Rashba spin-orbit interaction, incident angle, incident Fermi energy, and electric modulation potential. By tuning the modulation amplitude with gate voltage or the strength of RSOI modulation, efficient spin-polarized transport with P-Z=1 is achieved. This electric mechanism provides a convenient way to manipulate spin polarization, which can be experimentally verified.
SOLID STATE COMMUNICATIONS
(2022)
Article
Materials Science, Multidisciplinary
A. N. Mihalyuk, L. Bondarenko, A. Y. Tupchaya, T. Utas, Y. E. Vekovshinin, D. Gruznev, S. Eremeev, A. Zotov, A. A. Saranin
Summary: In this study, we investigated the atomic, electronic, and spin structures of single-atomic-layer PbBi compounds grown on a silicon surface, revealing different structural arrangements in different phases and discussing their influence on electronic states.
Article
Physics, Multidisciplinary
M. Maekawa, A. Miyashita, S. Sakai, S. Li, S. Entani, A. Kawasuso, Y. Sakuraba
Summary: By using spin-polarized positrons, researchers studied the surface density of states of various materials and found characteristic negative spin polarizations on Ni and Co surfaces, which disappeared upon deposition of graphene. The surface properties of CFGG and CMS exhibited weak spin polarizations, suggesting that the expected half-metallicity of these bulk states was not present at the surfaces.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Ching Hua Lee, Justin C. W. Song
Summary: When a topological phase is quenched into a gapped trivial phase, the characteristics of states prepared in the initial system can persist long after the quench. The topological boundary mode profiles decay slowly in a power-law fashion after a near-stationary window post-quench. Floquet topological engineering involves driving a trivial system into a transitory non-trivial state, with many open questions about the underlying mechanisms. The time evolution of a topological mode in a driven bulk band structure is theoretically investigated, showing unexpectedly long survival in a frozen regime before gradually disappearing in the melting regime.
COMMUNICATIONS PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Svetlana V. Gudina, Vladimir N. Neverov, Mikhail R. Popov, Konstantin V. Turutkin, Sergey M. Podgornykh, Nina G. Shelushinina, Mikhail V. Yakunin, Nikolay N. Mikhailov, Sergey A. Dvoretsky
Summary: By studying the Shubnikov-de-Haas oscillations, it is found that the Rashba spin-splitting in quantum wells with both a normal and inverted band structure is large and similar, with a value of 25-27 meV. This can be explained by the significant presence of p-type wave functions.
Article
Chemistry, Inorganic & Nuclear
Dabao Xie, Yang Shen, Jianguo Wan, Baoling Wang, Xiaodong Yang
Summary: III-V photocathodes with highly sensitive photoelectric response and broad spectral response have great potential as key components for optoelectronic devices. However, the absence of spin electrons in these traditional III-V materials limits the application of spin-polarized detection. In this study, we demonstrate that Cs adsorption on the H-GaBi surface enhances the emissions of topological spin electrons through negative electron affinity (NEA). The Cs@H-GaBi surface exhibits non-trivial edge states and under the NEA effect, topological spin electrons spontaneously enter the vacuum, resulting in efficient and selective spintronic emission.
INORGANIC CHEMISTRY COMMUNICATIONS
(2023)
Article
Chemistry, Multidisciplinary
An-Qi Wang, Peng-Zhan Xiang, Xing-Guo Ye, Wen-Zhuang Zheng, Dapeng Yu, Zhi-Min Liao
Summary: The study reveals the mechanism of antisymmetric linear MR in the spin transport of Dirac semimetal Cd3As2 nanoplates, which can be eliminated through sample surface modifications, leading to clean signals of charge current induced spin-polarized transport. The purification of spin signals is attributed to the isolation of surface and bulk transport channels.
Article
Physics, Multidisciplinary
Haoran Xue, Ding Jia, Yong Ge, Yi-jun Guan, Qiang Wang, Shou-qi Yuan, Hong-xiang Sun, Y. D. Chong, Baile Zhang
Summary: The study reveals the helical modes induced by dislocations in three-dimensional topological insulators, and experimentally observes and numerically verifies these modes serving as robust waveguides in three-dimensional media.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Condensed Matter
Liangzhong Lin, Guohui Zhan, Yiyun Ling, Wenkai Lou, Zhenhua Wu
Summary: In this study, we theoretically investigate the electron transport through HgTe/CdTe quantum well heterostructure interfaces and discover the unique Fabry-Perot resonant tunneling. We also analyze the methods to adjust the transport properties and enhance the resonance tunneling through electrical modulation. This research is of great significance for controlling electron transport in two-dimensional topological insulators from a device application perspective.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Wei-Tao Lu, Qing-Feng Sun, Yun-Fang Li, Hong-Yu Tian
Summary: Through adjusting the side potential and ribbon width, different spin- and valley-related electronic properties, such as quantum spin-valley Hall effect and spin-polarized quantum anomalous Hall effect, can be achieved in 2D honeycomb lattices with intrinsic spin-orbit coupling. The results indicate that the side potential has a significant impact on helical edge states, spins with different indices, and the locking of spin and valley.
Article
Nanoscience & Nanotechnology
J. Feilhauer, M. Zelent, Zhiwang Zhang, J. Christensen, M. Mruczkiewicz
Summary: We demonstrate a numerical simulation of magnonic crystals with unidirectional, topologically protected edge states. The crystal is composed of dipolarly coupled Permalloy triangles, and we show that the structure can be scaled up due to its geometry. Edge states can be found over a wide frequency range, and experimental detection can be done using state-of-the-art techniques. We present a proof-of-concept magnonic Chern topological insulator nanostructure with a simple geometry feasible for experimental realization. Additionally, we demonstrate a magnonic switch by inducing a topological phase transition that changes the direction of the topological edge state.
Article
Physics, Multidisciplinary
Yun-Lei Sun, Guo-Hong Chen, Si-Chao Du, Zhong-Bao Chen, Yan-Wei Zhou, En-Jia Ye
Summary: The spin-valley-related electronic properties of quasi-one-dimensional kagome lattices with intrinsic spin-orbit coupling are studied. It is found that spin-valley polarized edge states exist in the nanoribbons with different geometric boundaries, which has potential applications in devices.
FRONTIERS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Faezeh Pirmoradian, MirFaez Miri, Babak Zare Rameshti, Shahpoor Saeidian
Summary: We investigate the topological properties of a bipartite chain of magnetic spheres in a metallic waveguide. The chain, coherently coupled via the waveguide mode, exhibits two distinct phases distinguished by the Zak phase. In the presence of strong intercoupling, a finite chain supports doubly degenerate topological edge states within the gap, showing the preservation of the bulk-edge correspondence despite the strong coupling to the waveguide mode. The nontrivial (trivial) topological phase is determined by the intracell and intercell coupling of magnetic spheres, which depend on the separation, external magnetic inductions, and waveguide dimensions. Magnetically tunable topological magnon modes could enable novel topological photonic devices.
Article
Nanoscience & Nanotechnology
Vivekananda Adak, Krishanu Roychowdhury, Sourin Das
Summary: Theoretical models of a spin-polarized voltage probe (SPVP) tunnel-coupled to the helical edge states (HES) of a quantum spin Hall system (QSHS) are studied. The optimal situation for reading off spin-resolved voltage from the HES depends on the interplay of the probe-edge tunnel-coupling and the number of modes in the probe (N-P). The stability of the findings is investigated by introducing Gaussian fluctuations in the tunnel-coupling and spin-polarization. Another model employs the edge state of a quantum anomalous Hall state (QAHS) as the SPVP and demonstrates the feasibility of using it as an efficient spin-polarized voltage probe.
PHYSICA E-LOW-DIMENSIONAL SYSTEMS & NANOSTRUCTURES
(2022)
Article
Chemistry, Physical
Ziqi Han, Hua Hao, Xiaohong Zheng, Zhi Zeng
Summary: In this study, the spin-dependent transport properties of zigzag graphene nanoribbons (ZGNR) with asymmetric edge hydrogenation and different magnetic configurations were investigated using the non-equilibrium Green's function method combined with density functional calculations. The results showed that changing the magnetic configurations of the electrodes from parallel to antiparallel resulted in substantial changes in the currents in the tunnel junction, leading to a high conductance state and a low conductance state with a tunnel magnetoresistance (TMR) ratio larger than 1 x 10(5)%. Furthermore, an ideal bipolar spin filtering effect was observed in the parallel magnetic configurations, allowing for flexible switching of the spin polarity of current by reversing the bias direction. These findings indicate that asymmetric edge hydrogenation provides an important approach for constructing multi-functional spintronic devices with ZGNRs.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2023)
Article
Physics, Multidisciplinary
Yi-Wen Liu, Zhe Hou, Si-Yu Li, Qing-Feng Sun, Lin He
PHYSICAL REVIEW LETTERS
(2020)
Article
Physics, Multidisciplinary
Qing Yan, Yan-Feng Zhou, Qing-Feng Sun
Article
Physics, Multidisciplinary
Qing Yan, Hailong Li, Jiang Zeng, Qing-Feng Sun, X. C. Xie
Summary: An axion insulator is introduced theoretically with unique surface states with half-integer Chern number C. Theoretical analysis shows that a topological phase transition and emergence of a chiral Majorana hinge mode on the surface occur in proximity to a superconductor. A quantized thermal Hall conductance signature of the gapless chiral Majorana mode confirms the topological nature of the axion state.
COMMUNICATIONS PHYSICS
(2021)
Article
Multidisciplinary Sciences
Qi Zheng, Yu-Chen Zhuang, Qing-Feng Sun, Lin He
Summary: This study demonstrates that the electron whispering-gallery modes and atomic collapse states can coexist in graphene/WSe2 heterostructure quantum dots.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Physical
Pei-Jia Hu, Si-Xian Wang, Xiao-Feng Chen, Zeng-Ren Liang, Tie-Feng Fang, Ai-Min Guo, Hui Xu, Qing-Feng Sun
Summary: Recently, borophene has attracted extensive interest as a wonder material. It has been found that line defects (LDs) occur widely at the interface between v(1/5) and v(1/6) boron sheets. Theoretical study shows that LDs strongly affect the electron transport properties of disordered borophene nanoribbons (BNRs). The presence of LDs leads to a dramatic decrease in the overall electron transport ability, but some resonant peaks of conductance quantum are found in the transmission spectrum of any disordered BNR with arbitrary arrangement of LDs.
NPJ COMPUTATIONAL MATERIALS
(2022)
Article
Materials Science, Multidisciplinary
Yu-Chen Zhuang, Qing-Feng Sun
Summary: The wavefront dislocation is an important and ubiquitous phenomenon in wave fields, closely related to phase singularities. Recent studies have shown that wavefront dislocations in the local density of states map can well manifest intrinsic topological characteristics in graphene and other topological systems. We propose a transport method to measure wavefront dislocations in monolayer and Bernal-stacked bilayer graphene, combining analytical analysis and numerical calculation.
Article
Materials Science, Multidisciplinary
Qiang Cheng, Qing-Feng Sun
Summary: We propose a theoretical Josephson diode made of conventional superconductors with plain s-wave pairing and a chiral quantum dot. The critical current of the diode is different for opposite directions of current flow when an external magnetic field is applied to the quantum dot. Strong nonreciprocity can be achieved in a large parameter space, and it can be easily controlled by adjusting the direction of the external field. The dependence of nonreciprocal behavior on hopping amplitude, magnetic field magnitude, and quantum dot energy level is studied in detail using the Keldysh nonequilibrium Green's function formalism under a self-consistent procedure.
Article
Materials Science, Multidisciplinary
Shu-Chang Zhao, Lu Gao, Qiang Cheng, Qing-Feng Sun
Summary: This study investigates the crossed Andreev reflection and nonlocal transport in proximitized graphene/superconductor/proximitized graphene junctions with pseudospin staggered potential and intrinsic spin-orbit coupling. When the intrinsic spin-orbit couplings in the left and right graphene have opposite signs, the crossed Andreev reflection, coexisting with the local Andreev reflection and elastic cotunneling, can be completely eliminated for electrons with specific spin-valley indices. A perfect crossed Andreev reflection with a probability of 100% is achieved in the space of incident angle and electron energy. The crossed conductance and its dependence on superconductor length are also investigated. The energy ranges for the crossed Andreev reflection, without the local Andreev reflection and elastic cotunneling, are clarified for different magnitudes of the pseudospin potential and spin-orbit coupling. The spin-valley index of electrons responsible for the perfect crossed Andreev reflection can be controlled by changing the sign of the intrinsic spin-orbit coupling or applying different biases to the left and right graphene. These results are useful for designing flexible and highly efficient Cooper pair splitters based on spin-valley degree of freedom.
Article
Materials Science, Multidisciplinary
Yu -Chen Zhuang, Qing-Feng Sun
Summary: This study investigates the evolution of edge states between three peculiar topological insulating phases in graphene. The phase diagrams show that the real magnetic field and the pseudomagnetic field compete above the SOC energy gap, while the QSH effect is almost unaffected within the SOC energy gap. The transitions of edge states directly depend on the arrangement of the zeroth Landau levels. By utilizing these edge-state transitions, a spin-FET-like device and a spintronics multiple-way switch are proposed.
Article
Materials Science, Multidisciplinary
Yuchen Zhuang, Qing-Feng Sun
Summary: The photon-assisted tunneling of Majorana bound states in a Majorana nanowire driven by the periodic field is studied. The study reveals the anomalous photon-assisted tunneling signal of Majorana bound states and provides a systematic scheme to directly measure the Bardeen-Cooper-Schrieffer (BCS) information of overlapping Majorana bound states.
Article
Materials Science, Multidisciplinary
Cheng-Ming Miao, Qing-Feng Sun, Ying-Tao Zhang
Summary: We study the energy spectrum and transport property of a one-dimensional Kitaev quantum ring in a threading magnetic field. It is demonstrated that the field can induce topological phase transitions and control the appearance of Majorana zero-energy states. By calculating the transport properties, resonant peaks of the transmission coefficient correspond to the critical points of topological phase transition. The findings have important implications for understanding topological quantum phase transitions and realizing quantum information processing.
Article
Materials Science, Multidisciplinary
Qiang Cheng, Qing Yan, Qing-Feng Sun
Summary: Our study reveals that the Josephson effect in spin-triplet superconductor-quantum anomalous Hall insulator-spin-triplet superconductor junctions strongly depends on the orientations of the d vectors in superconductors, showing different effects for different configurations.
Article
Physics, Multidisciplinary
Zhe Hou, Qing-Feng Sun
PHYSICAL REVIEW RESEARCH
(2020)
Article
Materials Science, Multidisciplinary
Ning-Xuan Yang, Qing Yan, Qing-Feng Sun
Article
Materials Science, Multidisciplinary
Ning-Xuan Yang, Zhe Hou, Qing-Feng Sun
