1
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Reinhardt S, Ascherl T, Costa A, Berger J, Gronin S, Gardner GC, Lindemann T, Manfra MJ, Fabian J, Kochan D, Strunk C, Paradiso N. Link between supercurrent diode and anomalous Josephson effect revealed by gate-controlled interferometry. Nat Commun 2024; 15:4413. [PMID: 38782910 PMCID: PMC11116472 DOI: 10.1038/s41467-024-48741-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 05/07/2024] [Indexed: 05/25/2024] Open
Abstract
In Josephson diodes the asymmetry between positive and negative current branch of the current-phase relation leads to a polarity-dependent critical current and Josephson inductance. The supercurrent nonreciprocity can be described as a consequence of the anomalous Josephson effect -a φ0-shift of the current-phase relation- in multichannel ballistic junctions with strong spin-orbit interaction. In this work, we simultaneously investigate φ0-shift and supercurrent diode efficiency on the same Josephson junction by means of a superconducting quantum interferometer. By electrostatic gating, we reveal a direct link between φ0-shift and diode effect. Our findings show that spin-orbit interaction in combination with a Zeeman field plays an important role in determining the magnetochiral anisotropy and the supercurrent diode effect.
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Affiliation(s)
- S Reinhardt
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - T Ascherl
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - A Costa
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - J Berger
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Gronin
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - G C Gardner
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - T Lindemann
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - M J Manfra
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - J Fabian
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - D Kochan
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
- Center for Quantum Frontiers of Research and Technology (QFort), National Cheng Kung University, Tainan, Taiwan
| | - C Strunk
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - N Paradiso
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany.
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2
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Le T, Zhang R, Li C, Jiang R, Sheng H, Tu L, Cao X, Lyu Z, Shen J, Liu G, Liu F, Wang Z, Lu L, Qu F. Magnetic field filtering of the boundary supercurrent in unconventional metal NiTe 2-based Josephson junctions. Nat Commun 2024; 15:2785. [PMID: 38555347 PMCID: PMC10981750 DOI: 10.1038/s41467-024-47103-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 03/15/2024] [Indexed: 04/02/2024] Open
Abstract
Topological materials with boundary (surface/edge/hinge) states have attracted tremendous research interest. Additionally, unconventional (obstructed atomic) materials have recently drawn lots of attention owing to their obstructed boundary states. Experimentally, Josephson junctions (JJs) constructed on materials with boundary states produce the peculiar boundary supercurrent, which was utilized as a powerful diagnostic approach. Here, we report the observations of boundary supercurrent in NiTe2-based JJs. Particularly, applying an in-plane magnetic field along the Josephson current can rapidly suppress the bulk supercurrent and retain the nearly pure boundary supercurrent, namely the magnetic field filtering of supercurrent. Further systematic comparative analysis and theoretical calculations demonstrate the existence of unconventional nature and obstructed hinge states in NiTe2, which could produce hinge supercurrent that accounts for the observation. Our results reveal the probable hinge states in unconventional metal NiTe2, and demonstrate in-plane magnetic field as an efficient method to filter out the bulk contributions and thereby to highlight the hinge states hidden in topological/unconventional materials.
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Affiliation(s)
- Tian Le
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
| | - Ruihan Zhang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Changcun Li
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China
| | - Ruiyang Jiang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Haohao Sheng
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Linfeng Tu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- School of Physics, Nankai University, Tianjin, China
| | - Xuewei Cao
- School of Physics, Nankai University, Tianjin, China
| | - Zhaozheng Lyu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Hefei National Laboratory, Hefei, China
| | - Jie Shen
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China
| | - Guangtong Liu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China
- Hefei National Laboratory, Hefei, China
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China
| | - Fucai Liu
- School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, China.
- Yangtze Delta Region Institute (Huzhou), University of Electronic Science and Technology of China, Huzhou, China.
| | - Zhijun Wang
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
| | - Li Lu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Hefei National Laboratory, Hefei, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China.
| | - Fanming Qu
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing, China.
- School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, China.
- Hefei National Laboratory, Hefei, China.
- Songshan Lake Materials Laboratory, Dongguan, Guangdong, China.
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3
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Zhang SB, Hu LH, Neupert T. Finite-momentum Cooper pairing in proximitized altermagnets. Nat Commun 2024; 15:1801. [PMID: 38413591 PMCID: PMC10899178 DOI: 10.1038/s41467-024-45951-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Accepted: 02/08/2024] [Indexed: 02/29/2024] Open
Abstract
Finite-momentum Cooper pairing is an unconventional form of superconductivity that is widely believed to require finite magnetization. Altermagnetism is an emerging magnetic phase with highly anisotropic spin-splitting of specific symmetries, but zero net magnetization. Here, we study Cooper pairing in metallic altermagnets connected to conventional s-wave superconductors. Remarkably, we find that the Cooper pairs induced in the altermagnets acquire a finite center-of-mass momentum, despite the zero net magnetization in the system. This anomalous Cooper-pair momentum strongly depends on the propagation direction and exhibits unusual symmetric patterns. Furthermore, it yields several unique features: (i) highly orientation-dependent oscillations in the order parameter, (ii) controllable 0-π transitions in the Josephson supercurrent, (iii) large-oblique-angle Cooper-pair transfer trajectories in junctions parallel with the direction where spin splitting vanishes, and (iv) distinct Fraunhofer patterns in junctions oriented along different directions. Finally, we discuss the implementation of our predictions in candidate materials such as RuO2 and KRu4O8.
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Affiliation(s)
- Song-Bo Zhang
- Hefei National Laboratory, Hefei, Anhui, 230088, China.
- International Center for Quantum Design of Functional Materials (ICQD), University of Science and Technology of China, Hefei, Anhui, 230026, China.
- Department of Physics, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland.
| | - Lun-Hui Hu
- Department of Applied Physics, Aalto University School of Science, FI-00076, Aalto, Finland.
- Center for Correlated Matter and School of Physics, Zhejiang University, Hangzhou, 310058, China.
- Department of Physics and Astronomy, The University of Tennessee, Knoxville, TN, 37996, USA.
| | - Titus Neupert
- Department of Physics, University of Zürich, Winterthurerstrasse 190, 8057, Zürich, Switzerland
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4
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Costa A, Baumgartner C, Reinhardt S, Berger J, Gronin S, Gardner GC, Lindemann T, Manfra MJ, Fabian J, Kochan D, Paradiso N, Strunk C. Sign reversal of the Josephson inductance magnetochiral anisotropy and 0-π-like transitions in supercurrent diodes. NATURE NANOTECHNOLOGY 2023; 18:1266-1272. [PMID: 37430040 DOI: 10.1038/s41565-023-01451-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/09/2023] [Indexed: 07/12/2023]
Abstract
The recent discovery of the intrinsic supercurrent diode effect, and its prompt observation in a rich variety of systems, has shown that non-reciprocal supercurrents naturally emerge when both space-inversion and time-inversion symmetries are broken. In Josephson junctions, non-reciprocal supercurrent can be conveniently described in terms of spin-split Andreev states. Here we demonstrate a sign reversal of the Josephson inductance magnetochiral anisotropy, a manifestation of the supercurrent diode effect. The asymmetry of the Josephson inductance as a function of the supercurrent allows us to probe the current-phase relation near equilibrium, and to probe jumps in the junction ground state. Using a minimal theoretical model, we can then link the sign reversal of the inductance magnetochiral anisotropy to the so-called 0-π-like transition, a predicted but still elusive feature of multichannel junctions. Our results demonstrate the potential of inductance measurements as sensitive probes of the fundamental properties of unconventional Josephson junctions.
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Affiliation(s)
- A Costa
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - C Baumgartner
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Reinhardt
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - J Berger
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
| | - S Gronin
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - G C Gardner
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
| | - T Lindemann
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
| | - M J Manfra
- Birck Nanotechnology Center, Purdue University, West Lafayette, IN, USA
- Department of Physics and Astronomy, Purdue University, West Lafayette, IN, USA
- School of Materials Engineering, Purdue University, West Lafayette, IN, USA
- Elmore Family School of Electrical and Computer Engineering, Purdue University, West Lafayette, IN, USA
| | - J Fabian
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
| | - D Kochan
- Institut für Theoretische Physik, University of Regensburg, Regensburg, Germany
- Institute of Physics, Slovak Academy of Sciences, Bratislava, Slovakia
| | - N Paradiso
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany.
| | - C Strunk
- Institut für Experimentelle und Angewandte Physik, University of Regensburg, Regensburg, Germany
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5
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Pal B, Chakraborty A, Sivakumar PK, Davydova M, Gopi AK, Pandeya AK, Krieger JA, Zhang Y, Date M, Ju S, Yuan N, Schröter NBM, Fu L, Parkin SSP. Josephson diode effect from Cooper pair momentum in a topological semimetal. NATURE PHYSICS 2022; 18:1228-1233. [PMID: 36217362 PMCID: PMC9537108 DOI: 10.1038/s41567-022-01699-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Accepted: 06/29/2022] [Indexed: 05/16/2023]
Abstract
Cooper pairs in non-centrosymmetric superconductors can acquire finite centre-of-mass momentum in the presence of an external magnetic field. Recent theory predicts that such finite-momentum pairing can lead to an asymmetric critical current, where a dissipationless supercurrent can flow along one direction but not in the opposite one. Here we report the discovery of a giant Josephson diode effect in Josephson junctions formed from a type-II Dirac semimetal, NiTe2. A distinguishing feature is that the asymmetry in the critical current depends sensitively on the magnitude and direction of an applied magnetic field and achieves its maximum value when the magnetic field is perpendicular to the current and is of the order of just 10 mT. Moreover, the asymmetry changes sign several times with an increasing field. These characteristic features are accounted for by a model based on finite-momentum Cooper pairing that largely originates from the Zeeman shift of spin-helical topological surface states. The finite pairing momentum is further established, and its value determined, from the evolution of the interference pattern under an in-plane magnetic field. The observed giant magnitude of the asymmetry in critical current and the clear exposition of its underlying mechanism paves the way to build novel superconducting computing devices using the Josephson diode effect.
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Affiliation(s)
- Banabir Pal
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | | | | | - Margarita Davydova
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Ajesh K. Gopi
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | | | - Jonas A. Krieger
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Yang Zhang
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | - Mihir Date
- Max Planck Institute of Microstructure Physics, Halle (Saale), Germany
| | - Sailong Ju
- Swiss Light Source, Paul Scherrer Institute, Villigen PSI, Switzerland
| | - Noah Yuan
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
| | | | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA USA
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6
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Zhu Z, Papaj M, Nie XA, Xu HK, Gu YS, Yang X, Guan D, Wang S, Li Y, Liu C, Luo J, Xu ZA, Zheng H, Fu L, Jia JF. Discovery of segmented Fermi surface induced by Cooper pair momentum. Science 2021; 374:1381-1385. [PMID: 34709939 DOI: 10.1126/science.abf1077] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Zhen Zhu
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Michał Papaj
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Xiao-Ang Nie
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Hao-Ke Xu
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yi-Sheng Gu
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xu Yang
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Dandan Guan
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Shiyong Wang
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Yaoyi Li
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Canhua Liu
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Jianlin Luo
- Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
| | - Zhu-An Xu
- Department of Physics, Zhejiang University, Hangzhou 310027, Zhejiang, China
| | - Hao Zheng
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jin-Feng Jia
- School of Physics and Astronomy, Key Laboratory of Artificial Structures and Quantum Control (Ministry of Education), Shenyang National Laboratory for Materials Science, Tsung-Dao Lee Institute, Shanghai Jiao Tong University, Shanghai 200240, China
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7
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Beach A, Reig-I-Plessis D, MacDougall G, Mason N. Asymmetric Fraunhofer spectra in a topological insulator-based Josephson junction. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:425601. [PMID: 34280900 DOI: 10.1088/1361-648x/ac15d7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2021] [Accepted: 07/19/2021] [Indexed: 06/13/2023]
Abstract
Josephson junctions with topological insulators as their weak link (S-TI-S junctions) are predicted to host Majorana fermions, which are key to creating qubits for topologically protected quantum computing. But the details of the S-TI-S current-phase relation and its interplay with magnetic fields are not well understood. We fabricate a Bi2Se3junction with NbTi leads and measure the Fraunhofer patterns of the junction with applied in-plane fields. We observe that asymmetric Fraunhofer patterns appear in the resistance maps ofBzvsBx,y, with aperiodic node spacings. These asymmetric patterns appear even at zero parallel field and for temperatures up to 1 K. The anomalous features are compared to asymmetric Fraunhofer patterns expected for finite Cooper pair momentum shifts as well as geometric effects. We show that the geometric effects can dominate, independent of in-plane field magnitude. These results are important for differentiating geometrical phase shifts from those caused by Cooper pair momentum shifting, Majorana mode signatures, or other unconventional superconducting behavior.
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Affiliation(s)
- Alexander Beach
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, 61801 IL, United States of America
| | - Dalmau Reig-I-Plessis
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, 61801 IL, United States of America
| | - Gregory MacDougall
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, 61801 IL, United States of America
| | - Nadya Mason
- Department of Physics and Materials Research Laboratory, University of Illinois, Urbana, 61801 IL, United States of America
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8
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Papaj M, Fu L. Creating Majorana modes from segmented Fermi surface. Nat Commun 2021; 12:577. [PMID: 33495471 PMCID: PMC7835351 DOI: 10.1038/s41467-020-20690-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Accepted: 12/15/2020] [Indexed: 11/09/2022] Open
Abstract
Majorana bound states provide a fertile ground for both investigation of fundamental phenomena as well as for applications in quantum computation. However, despite enormous experimental and theoretical efforts, the currently available Majorana platforms suffer from a multitude of issues that prevent full realization of their potential. Therefore, improved Majorana systems are still highly sought after. Here we present a platform for creating Majorana bound states from 2D gapless superconducting state in spin-helical systems under the in-plane magnetic or Zeeman field. Topological 1D channels are formed by quantum confinement of quasiparticles via Andreev reflection from the surrounding fully gapped superconducting region. Our proposal can be realized using narrow strips of magnetic insulators on top of proximitized 3D topological insulators. This setup has key advantages that include: small required fields, no necessity of fine-tuning of chemical potential, removal of the low-energy detrimental states, and large attainable topological gap.
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Affiliation(s)
- Michał Papaj
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| | - Liang Fu
- Department of Physics, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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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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Ballistic superconductivity and tunable π-junctions in InSb quantum wells. Nat Commun 2019; 10:3764. [PMID: 31434887 PMCID: PMC6704170 DOI: 10.1038/s41467-019-11742-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2019] [Accepted: 07/28/2019] [Indexed: 11/08/2022] Open
Abstract
Planar Josephson junctions (JJs) made in semiconductor quantum wells with large spin-orbit coupling are capable of hosting topological superconductivity. Indium antimonide (InSb) two-dimensional electron gases (2DEGs) are particularly suited for this due to their large Landé g-factor and high carrier mobility, however superconducting hybrids in these 2DEGs remain unexplored. Here we create JJs in high quality InSb 2DEGs and provide evidence of ballistic superconductivity over micron-scale lengths. A Zeeman field produces distinct revivals of the supercurrent in the junction, associated with a 0-π transition. We show that these transitions can be controlled by device design, and tuned in-situ using gates. A comparison between experiments and the theory of ballistic π-Josephson junctions gives excellent quantitative agreement. Our results therefore establish InSb quantum wells as a promising new material platform to study the interplay between superconductivity, spin-orbit interaction and magnetism.
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11
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Schönle J, Borisov K, Klett R, Dyck D, Balestro F, Reiss G, Wernsdorfer W. Field-Tunable 0-π-Transitions in SnTe Topological Crystalline Insulator SQUIDs. Sci Rep 2019; 9:1987. [PMID: 30760767 PMCID: PMC6374487 DOI: 10.1038/s41598-018-38008-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 12/17/2018] [Indexed: 11/08/2022] Open
Abstract
The manifestation of spin-orbit interactions, long known to dramatically affect the band structure of heavy-element compounds, governs the physics in the surging class of topological matter. A particular example is found in the new family of topological crystalline insulators. In this systems transport occurs at the surfaces and spin-momentum locking yields crystal-symmetry protected spin-polarized transport. We investigated the current-phase relation of SnTe thin films connected to superconducting electrodes to form SQUID devices. Our results demonstrate that an assisting in-plane magnetic field component can induce 0-π-transitions. We attribute these findings to giant g-factors and large spin-orbit coupling of SnTe topological crystalline insulator, which provides a new platform for investigation of the interplay between spin-orbit physics and topological transport.
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Affiliation(s)
- Joachim Schönle
- Institut Néel, CNRS and University Grenoble-Alpes, 25 Rue des Martyrs, F-38042, Grenoble, France.
- Physikalisches Institut (PHI), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, D-76131, Karlsruhe, Germany.
| | - Kiril Borisov
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76334, Eggenstein-Leopoldshafen, Germany.
| | - Robin Klett
- Center for Spinelectronic Materials & Devices, Physics Department, Bielefeld University, Universitätsstraße 25, D-33615, Bielefeld, Germany
| | - Denis Dyck
- Center for Spinelectronic Materials & Devices, Physics Department, Bielefeld University, Universitätsstraße 25, D-33615, Bielefeld, Germany
| | - Franck Balestro
- Institut Néel, CNRS and University Grenoble-Alpes, 25 Rue des Martyrs, F-38042, Grenoble, France
| | - Günter Reiss
- Center for Spinelectronic Materials & Devices, Physics Department, Bielefeld University, Universitätsstraße 25, D-33615, Bielefeld, Germany
| | - Wolfgang Wernsdorfer
- Institut Néel, CNRS and University Grenoble-Alpes, 25 Rue des Martyrs, F-38042, Grenoble, France
- Physikalisches Institut (PHI), Karlsruhe Institute of Technology (KIT), Wolfgang-Gaede-Straße 1, D-76131, Karlsruhe, Germany
- Institute of Nanotechnology (INT), Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz 1, D-76334, Eggenstein-Leopoldshafen, Germany
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12
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