Proximity-induced surface superconductivity in Dirac semimetal Cd3As2

• DOI: 10.1038/s41467-019-10233-w
• Publication Date: 2019-05-17T10:04:09Z
• Authors: 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
• Keywords: 0303 health sciences; 1300 Biochemistry; Science; Q; General Physics and Astronomy; Genetics and Molecular Biology; General Chemistry; 1600 Chemistry; 530; Article; 03 medical and health sciences; General Biochemistry; 3100 Physics and Astronomy

AbstractCd3As2 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.