Proximity-induced surface superconductivity in Dirac semimetal Cd3As2

Ce Huang; Benjamin T Zhou; Huiqin Zhang; Bingjia Yang; Ran Liu; Hanwen Wang; Yimin Wan; Ke Huang; Zhiming Liao; Enze Zhang; Shanshan Liu; Qingsong Deng; Yanhui Chen; Xiaodong Han; Jin Zou; Xi Lin; Zheng Han; Yihua Wang; Kam Tuen Law; Faxian Xiu

doi:10.1038/s41467-019-10233-w

Proximity-induced surface superconductivity in Dirac semimetal Cd₃As₂

Nat Commun. 2019 May 17;10(1):2217. doi: 10.1038/s41467-019-10233-w.

Authors

Ce Huang^{1

2}, Benjamin T Zhou³, Huiqin Zhang^{1

2}, Bingjia Yang^{1

2}, Ran Liu^{1

2}, Hanwen Wang⁴, Yimin Wan^{1

2}, Ke Huang⁵, Zhiming Liao⁶, Enze Zhang^{1

2}, Shanshan Liu^{1

2}, Qingsong Deng⁷, Yanhui Chen⁷, Xiaodong Han⁷, Jin Zou^{6

8}, Xi Lin⁵, Zheng Han⁴, Yihua Wang^{1

2}, Kam Tuen Law³, Faxian Xiu^{9

10

11}

Affiliations

¹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200433, China.
² Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China.
³ Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Hong Kong, China.
⁴ Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016, China.
⁵ International Center for Quantum Materials, Peking University, Beijing, 100871, China.
⁶ Materials Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia.
⁷ Beijing Key Laboratory of Microstructure and Property of Advanced Materials, Institute of Microstructure and Property of Advanced Materials, University of Technology, 100124, Beijing, China.
⁸ Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, QLD, 4072, Australia.
⁹ State Key Laboratory of Surface Physics and Department of Physics, Fudan University, Shanghai, 200433, China. Faxian@fudan.edu.cn.
¹⁰ Institute for Nanoelectronic Devices and Quantum Computing, Fudan University, Shanghai, 200433, China. Faxian@fudan.edu.cn.
¹¹ Collaborative Innovation Center of Advanced Microstructures, Nanjing, 210093, China. Faxian@fudan.edu.cn.

Abstract

Cd₃As₂ is a three-dimensional Dirac semimetal with separated Dirac points in momentum space. In spite of extensive transport and spectroscopic studies on its exotic properties, the evidence of superconductivity in its surface states remains elusive. Here, we report the observation of proximity-induced surface superconductivity in Nb/Cd₃As₂ hybrid structures. Our four-terminal transport measurement identifies a pronounced proximity-induced pairing gap (gap size comparable to Nb) on the surfaces, which exhibits a flat conductance plateau in differential conductance spectra, consistent with our theoretical simulations. The surface supercurrent from Nb/Cd₃As₂/Nb junctions is also achieved with a Fraunhofer/SQUID-like pattern under out-of-plane/in-plane magnetic fields, respectively. The resultant mapping shows a predominant distribution on the top and bottom surfaces as the bulk carriers are depleted, which can be regarded as a higher dimensional analog of edge supercurrent in two-dimensional quantum spin Hall insulators. Our study provides the evidence of surface superconductivity in Dirac semimetals.

Publication types

Research Support, Non-U.S. Gov't