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Chen J, Xu W, Tan Z, Pan Z, Zhu P, Liao ZM, Yu D. Superconducting Proximity in Intrinsic Magnetic Topological Insulator MnBi 2Te 4-NbN Hybrid Device Modulated by Coulomb Blockade Effect. NANO LETTERS 2022; 22:6484-6491. [PMID: 35926195 DOI: 10.1021/acs.nanolett.2c00948] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The combination of nontrivial topology, magnetism, and superconductivity could offer the potential to realize exotic excitations of quasiparticles. MnBi2Te4, as an intrinsic magnetic topological insulator, may be a good platform to create Majorana fermions if coupled to an s-wave superconductor. Here, we report the transport properties of a MnBi2Te4-NbN hybrid device. This device exhibits clear Coulomb blockade oscillations. We observe a large zero-bias conductance peak that exists over considerable changes in gate voltage, magnetic field, and temperature, which is interpreted as a not fully developed supercurrent. The zero-bias peak shows a nonmonotonic evolution with a magnetic field and an abrupt π phase shift with changing temperature. Zero-energy bound states and a topological phase transition may exist in this hybrid system. Our results provide the first experimental investigation into the properties of the intrinsic magnetic topological insulator/superconductor hybrid structures modulated by the Coulomb blockade effect.
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Affiliation(s)
- Jingjing Chen
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
| | - Wenzheng Xu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zhenbing Tan
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
| | - Zhencun Pan
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Pengfei Zhu
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Dapeng Yu
- Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
- International Quantum Academy, Shenzhen 518048, China
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, China
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2
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Yu W, Rademacher DX, Valdez NR, Rodriguez MA, Nenoff TM, Pan W. Evidence of decoupling of surface and bulk states in Dirac semimetal Cd 3As 2. NANOTECHNOLOGY 2022; 33:415002. [PMID: 35760060 DOI: 10.1088/1361-6528/ac7c25] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/27/2022] [Indexed: 06/15/2023]
Abstract
Dirac semimetals have attracted a great deal of current interests due to their potential applications in topological quantum computing, low-energy electronic devices, and single photon detection in the microwave frequency range. Herein are results from analyzing the low magnetic (B) field weak-antilocalization behaviors in a Dirac semimetal Cd3As2thin flake device. At high temperatures, the phase coherence lengthlϕfirst increases with decreasing temperature (T) and follows a power law dependence oflϕ∝T-0.4. Below ∼3 K,lϕtends to saturate to a value of ∼180 nm. Another fitting parameterα, which is associated with independent transport channels, displays a logarithmic temperature dependence forT > 3 K, but also tends to saturate below ∼3 K. The saturation value, ∼1.45, is very close to 1.5, indicating three independent electron transport channels, which we interpret as due to decoupling of both the top and bottom surfaces as well as the bulk. This result, to our knowledge, provides first evidence that the surfaces and bulk states can become decoupled in electronic transport in Dirac semimetal Cd3As2.
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Affiliation(s)
- W Yu
- Sandia National Laboratories, Albuquerque, New Mexico NM-87185, United States of America
| | - D X Rademacher
- Sandia National Laboratories, Albuquerque, New Mexico NM-87185, United States of America
| | - N R Valdez
- Sandia National Laboratories, Albuquerque, New Mexico NM-87185, United States of America
| | - M A Rodriguez
- Sandia National Laboratories, Albuquerque, New Mexico NM-87185, United States of America
| | - T M Nenoff
- Sandia National Laboratories, Albuquerque, New Mexico NM-87185, United States of America
| | - W Pan
- Sandia National Laboratories, Livermore, California CA-94551, United States of America
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3
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Microwave response in a topological superconducting quantum interference device. Sci Rep 2021; 11:8615. [PMID: 33883640 PMCID: PMC8060411 DOI: 10.1038/s41598-021-88035-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/05/2021] [Indexed: 12/03/2022] Open
Abstract
Photon detection at microwave frequency is of great interest due to its application in quantum computation information science and technology. Herein are results from studying microwave response in a topological superconducting quantum interference device (SQUID) realized in Dirac semimetal Cd3As2. The temperature dependence and microwave power dependence of the SQUID junction resistance are studied, from which we obtain an effective temperature at each microwave power level. It is observed the effective temperature increases with the microwave power. This observation of large microwave response may pave the way for single photon detection at the microwave frequency in topological quantum materials.
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Li CZ, Wang AQ, Li C, Zheng WZ, Brinkman A, Yu DP, Liao ZM. Topological Transition of Superconductivity in Dirac Semimetal Nanowire Josephson Junctions. PHYSICAL REVIEW LETTERS 2021; 126:027001. [PMID: 33512215 DOI: 10.1103/physrevlett.126.027001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Accepted: 12/18/2020] [Indexed: 06/12/2023]
Abstract
We report the topological transition by gate control in a Cd_{3}As_{2} Dirac semimetal nanowire Josephson junction with diameter of about 64 nm. In the electron branch, the quantum confinement effect enforces the surface band into a series of gapped subbands and thus nontopological states. In the hole branch, however, because the hole mean free path is smaller than the nanowire perimeter, the quantum confinement effect is inoperative and the topological property maintained. The superconductivity is enhanced by gate tuning from electron to hole conduction, manifested by a larger critical supercurrent and a larger critical magnetic field, which is attributed to the topological transition from gapped surface subbands to a gapless surface band. The gate-controlled topological transition of superconductivity should be valuable for manipulation of Majorana zero modes, providing a platform for future compatible and scalable design of topological qubits.
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Affiliation(s)
- Cai-Zhen Li
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - An-Qi Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Chuan Li
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Wen-Zhuang Zheng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Da-Peng Yu
- Shenzhen Institute for Quantum Science and Engineering, and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Beijing Key Laboratory of Quantum Devices, Peking University, Beijing 100871, China
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5
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Yan Z, Wu Z, Huang W. Vortex End Majorana Zero Modes in Superconducting Dirac and Weyl Semimetals. PHYSICAL REVIEW LETTERS 2020; 124:257001. [PMID: 32639774 DOI: 10.1103/physrevlett.124.257001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 06/01/2020] [Accepted: 06/02/2020] [Indexed: 06/11/2023]
Abstract
Time-reversal invariant Dirac and Weyl semimetals in three dimensions (3D) can host open Fermi arcs and spin-momentum locking Fermi loops on the surfaces. We find that when they become superconducting with s-wave pairing and the doping is lower than a critical level, straight π-flux vortex lines terminating at surfaces with Fermi arcs or spin-momentum locking Fermi loops can realize 1D topological superconductivity and harbor Majorana zero modes at their ends. Remarkably, we find that the vortex-generation-associated Zeeman field can open (when the surfaces have only Fermi arcs) or enhance the topological gap protecting Majorana zero modes, which is contrary to the situation in superconducting topological insulators. By studying the tilting effect of bulk Dirac and Weyl cones, we further find that type-I Dirac and Weyl semimetals in general have a much broader topological regime than type-II ones. Our findings build up a connection between time-reversal invariant Dirac and Weyl semimetals and Majorana zero modes in vortices.
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Affiliation(s)
- Zhongbo Yan
- School of Physics, Sun Yat-Sen University, Guangzhou 510275, China
| | - Zhigang Wu
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
| | - Wen Huang
- Guangdong Provincial Key Laboratory of Quantum Science and Engineering, Shenzhen Institute for Quantum Science and Engineering, Southern University of Science and Technology, Shenzhen 518055, Guangdong, China
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6
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Wang AQ, Ye XG, Yu DP, Liao ZM. Topological Semimetal Nanostructures: From Properties to Topotronics. ACS NANO 2020; 14:3755-3778. [PMID: 32286783 DOI: 10.1021/acsnano.9b07990] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Characterized by bulk Dirac or Weyl cones and surface Fermi-arc states, topological semimetals have sparked enormous research interest in recent years. The nanostructures, with large surface-to-volume ratio and easy field-effect gating, provide ideal platforms to detect and manipulate the topological quantum states. Exotic physical properties originating from these topological states endow topological semimetals attractive for future topological electronics (topotronics). For example, the linear energy dispersion relation is promising for broadband infrared photodetectors, the spin-momentum locking nature of topological surface states is valuable for spintronics, and the topological superconductivity is highly desirable for fault-tolerant qubits. For real-life applications, topological semimetals in the form of nanostructures are necessary in terms of convenient fabrication and integration. Here, we review the recent progresses in topological semimetal nanostructures and start with the quantum transport properties. Then topological semimetal-based electronic devices are introduced. Finally, we discuss several important aspects that should receive great effort in the future, including controllable synthesis, manipulation of quantum states, topological field effect transistors, spintronic applications, and topological quantum computation.
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Affiliation(s)
- An-Qi Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Xing-Guo Ye
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Da-Peng Yu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
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7
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Li CZ, Wang AQ, Li C, Zheng WZ, Brinkman A, Yu DP, Liao ZM. Reducing Electronic Transport Dimension to Topological Hinge States by Increasing Geometry Size of Dirac Semimetal Josephson Junctions. PHYSICAL REVIEW LETTERS 2020; 124:156601. [PMID: 32357024 DOI: 10.1103/physrevlett.124.156601] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 02/11/2020] [Accepted: 03/27/2020] [Indexed: 06/11/2023]
Abstract
The notion of topological phases has been extended to higher-order and has been generalized to different dimensions. As a paradigm, Cd_{3}As_{2} is predicted to be a higher-order topological semimetal, possessing three-dimensional bulk Dirac fermions, two-dimensional Fermi arcs, and one-dimensional hinge states. These topological states have different characteristic length scales in electronic transport, allowing one to distinguish their properties when changing sample size. Here, we report an anomalous dimensional reduction of supercurrent transport by increasing the size of Dirac semimetal Cd_{3}As_{2}-based Josephson junctions. An evolution of the supercurrent quantum interferences from a standard Fraunhofer pattern to a superconducting quantum interference device (SQUID)-like one is observed when the junction channel length is increased. The SQUID-like interference pattern indicates the supercurrent flowing through the 1D hinges. The identification of 1D hinge states should be valuable for deeper understanding of the higher-order topological phase in a 3D Dirac semimetal.
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Affiliation(s)
- Cai-Zhen Li
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - An-Qi Wang
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
| | - Chuan Li
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Wen-Zhuang Zheng
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands
| | - Da-Peng Yu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics and Frontiers Science Center for Nano-optoelectronics, School of Physics, Peking University, Beijing 100871, China
- Beijing Key Laboratory of Quantum Devices, and Collaborative Innovation Center of Quantum Matter, Peking University, Beijing 100871, China
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8
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Superconductivity and Shubnikov - de Haas effect in polycrystalline Cd 3As 2 thin films. Sci Rep 2020; 10:4601. [PMID: 32165644 PMCID: PMC7067877 DOI: 10.1038/s41598-020-61376-6] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/21/2020] [Indexed: 11/16/2022] Open
Abstract
In this study we observed the reproducible superconducting state in Cd3As2 thin films without any external stimuli. Comparison with our previous results reveals similar qualitative behavior for films synthesized by different methods, while the difference in the values of the critical parameters clearly shows the possibility to control this state. The X-ray diffraction measurements demonstrate the presence of the tetragonal Cd3As2 crystal phase in studied films. Measurements of high-field magnetoresistance reveal pronounced Shubnikov - de Haas oscillations. The analysis of these oscillations suggests that, due to high carrier concentration in studied Cd3As2 films, the initial Dirac semimetal phase may be partially suppressed, which, however, does not contradict with possible topological nature of the observed superconductivity.
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9
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Fermi-arc supercurrent oscillations in Dirac semimetal Josephson junctions. Nat Commun 2020; 11:1150. [PMID: 32123180 PMCID: PMC7051961 DOI: 10.1038/s41467-020-15010-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2019] [Accepted: 02/16/2020] [Indexed: 11/08/2022] Open
Abstract
One prominent hallmark of topological semimetals is the existence of unusual topological surface states known as Fermi arcs. Nevertheless, the Fermi-arc superconductivity remains elusive. Here, we report the critical current oscillations from surface Fermi arcs in Nb-Dirac semimetal Cd3As2-Nb Josephson junctions. The supercurrent from bulk states are suppressed under an in-plane magnetic field ~0.1 T, while the supercurrent from the topological surface states survives up to 0.5 T. Contrary to the minimum normal-state conductance, the Fermi-arc carried supercurrent shows a maximum critical value near the Dirac point, which is consistent with the fact that the Fermi arcs have maximum density of state at the Dirac point. Moreover, the critical current exhibits periodic oscillations with a parallel magnetic field, which is well understood by considering the in-plane orbital effect from the surface states. Our results suggest the Dirac semimetal combined with superconductivity should be promising for topological quantum devices.
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10
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Mohajerani A, Faraei Z, Jafari SA. NMR diagnosis of pseudo-scalar superconductivity in 3D Dirac materials. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:50LT01. [PMID: 30460922 DOI: 10.1088/1361-648x/aaeef7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Recently observed 4π periodic Andreev bound states in 3D Dirac materials are attributed to conventional superconducting pairing. Our alternative explanation in terms of a novel form of parity breaking pseudo-scalar superconducting order can be sharply diagnosed by nuclear magnetic resonance relaxation rate. The left-right symmetry breaking of the pseudo-scalar superconductivity can be directly probed as an anti-peak structure below T C in sharp contrast to the conventional Hebel-Slichter peak.
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Affiliation(s)
- Azin Mohajerani
- Department of Basic Science, Tarbiat Modares University (TMU), Tehran 14115-175, Iran
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11
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Wang AQ, Li CZ, Li C, Liao ZM, Brinkman A, Yu DP. 4π-Periodic Supercurrent from Surface States in Cd_{3}As_{2} Nanowire-Based Josephson Junctions. PHYSICAL REVIEW LETTERS 2018; 121:237701. [PMID: 30576175 DOI: 10.1103/physrevlett.121.237701] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Indexed: 06/09/2023]
Abstract
The combination of superconductivity and surface states in Dirac semimetal can produce a 4π-periodic supercurrent in a Josephson junction configuration, which can be revealed by the missing of odd Shapiro steps (especially the n=1 step). However, the suppression of the n=1 step is also anticipated in the high-power oscillatory regime of the ordinary 2π-periodic Josephson effect, which is irrelevant to the 4π-periodic supercurrent. Here, in order to identify the origin of the suppressed n=1 step, we perform the measurements of radio frequency irradiation on Nb-Dirac semimetal Cd_{3}As_{2} nanowire-Nb junctions with continuous power dependence at various frequencies. Besides the n=1 step suppression, we uncover a residual supercurrent of first node at the n=0 step, which provides a direct and predominant signature of the 4π-periodic supercurrent. Furthermore, by tuning the gate voltage, we can modulate the surface and bulk state contribution and the visibility of the n=1 step. Our results provide deep insights to explore the topological superconductivity in Dirac semimetals.
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Affiliation(s)
- An-Qi Wang
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing 100871, China
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
| | - Cai-Zhen Li
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
| | - Chuan Li
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
| | - Zhi-Min Liao
- State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China
- Beijing Key Laboratory of Quantum Devices, Peking University, Beijing 100871, China
- Collaborative Innovation Center of Quantum Matter, Beijing 100871, China
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, Netherlands
| | - Da-Peng Yu
- Shenzhen Institute for Quantum Science and Engineering and Department of Physics, Southern University of Science and Technology, Shenzhen 518055, China
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12
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Zhang SB, Erdmenger J, Trauzettel B. Chirality Josephson Current Due to a Novel Quantum Anomaly in Inversion-Asymmetric Weyl Semimetals. PHYSICAL REVIEW LETTERS 2018; 121:226604. [PMID: 30547657 DOI: 10.1103/physrevlett.121.226604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/21/2018] [Indexed: 06/09/2023]
Abstract
We study Josephson junctions based on inversion-asymmetric but time-reversal symmetric Weyl semimetals under the influence of Zeeman fields. We find that, due to distinct spin textures, the Weyl nodes of opposite chirality respond differently to an external magnetic field. Remarkably, a Zeeman field perpendicular to the junction direction results in a phase shift of opposite sign in the current-phase relations of opposite chirality. This leads to a finite chirality Josephson current (CJC) even in the absence of a phase difference across the junction. This feature could allow for applications in chiralitytronics. In the long junction and zero temperature limit, the CJC embodies a novel quantum anomaly of Goldstone bosons at π phase difference which is associated with a Z_{2} symmetry at low energies. It can be detected experimentally via an anomalous Fraunhofer pattern.
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Affiliation(s)
- Song-Bo Zhang
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany
| | - Johanna Erdmenger
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany
| | - Björn Trauzettel
- Institute for Theoretical Physics and Astrophysics, University of Würzburg, D-97074 Würzburg, Germany
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13
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Wang Q, Liu CC, Lu YM, Zhang F. High-Temperature Majorana Corner States. PHYSICAL REVIEW LETTERS 2018; 121:186801. [PMID: 30444417 DOI: 10.1103/physrevlett.121.186801] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 09/26/2018] [Indexed: 06/09/2023]
Abstract
Majorana bound states often occur at the end of a 1D topological superconductor. Validated by a new bulk invariant and an intuitive edge argument, we show the emergence of one Majorana Kramers pair at each corner of a square-shaped 2D topological insulator proximitized by an s_{±}-wave (e.g., Fe-based) superconductor. We obtain a phase diagram that addresses the relaxation of crystal symmetry and edge orientation. We propose two experimental realizations in candidate materials. Our scheme offers a higher-order and higher-temperature route for exploring non-Abelian quasiparticles.
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Affiliation(s)
- Qiyue Wang
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, USA
| | - Cheng-Cheng Liu
- School of Physics, Beijing Institute of Technology, Beijing 100081, China
| | - Yuan-Ming Lu
- Department of Physics, Ohio State University, Columbus, Ohio 43210, USA
| | - Fan Zhang
- Department of Physics, University of Texas at Dallas, Richardson, Texas 75080, USA
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14
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Li C, de Boer JC, de Ronde B, Ramankutty SV, van Heumen E, Huang Y, de Visser A, Golubov AA, Golden MS, Brinkman A. 4π-periodic Andreev bound states in a Dirac semimetal. NATURE MATERIALS 2018; 17:875-880. [PMID: 30224782 DOI: 10.1038/s41563-018-0158-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 07/30/2018] [Indexed: 05/12/2023]
Abstract
Although signatures of superconductivity in Dirac semimetals have been reported, for instance by applying pressure or using point contacts, our understanding of the topological aspects of Dirac semimetal superconductivity is still developing. Here, we utilize nanoscale phase-sensitive junction technology to induce superconductivity in the Dirac semimetal Bi1-xSbx. Our radiofrequency irradiation experiments then reveal a significant contribution of 4π-periodic Andreev bound states to the supercurrent in Nb-Bi0.97Sb0.03-Nb Josephson junctions. The conditions for a substantial 4π contribution to the supercurrent are favourable because of the Dirac cone's very broad transmission resonances and a measurement frequency faster than the quasiparticle poisoning rate. In addition, we show that a magnetic field applied in the plane of the junction allows tuning of the Josephson junctions from 0 to π regimes. Our results open the technologically appealing avenue of employing the topological bulk properties of Dirac semimetals for topological superconductivity research and topological quantum computer development.
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Affiliation(s)
- Chuan Li
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands
| | - Jorrit C de Boer
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands
| | - Bob de Ronde
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands
| | - Shyama V Ramankutty
- Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam, the Netherlands
| | - Erik van Heumen
- Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam, the Netherlands
| | - Yingkai Huang
- Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam, the Netherlands
| | - Anne de Visser
- Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam, the Netherlands
| | - Alexander A Golubov
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands
- Moscow Institute of Physics and Technology, Dolgoprudny, Moscow, Russia
| | - Mark S Golden
- Van der Waals-Zeeman Institute, IoP, University of Amsterdam, Amsterdam, the Netherlands
| | - Alexander Brinkman
- MESA+ Institute for Nanotechnology, University of Twente, Enschede, the Netherlands.
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15
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Affiliation(s)
- Fan Zhang
- Department of Physics, University of Texas at Dallas, Richardson, TX, USA.
| | - Wei Pan
- Sandia National Laboratories, Albuquerque, NM, and, Livermore, CA, USA.
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