Intrinsic surface p-wave superconductivity in layered AuSn4

• Published in: Nature communications 2023-11, Vol.14 (1), p.7012-7012, Article 7012
• Main Authors: Zhu, Wenliang, Song, Rui, Huang, Jierui, Wang, Qi-Wei, Cao, Yuan, Zhai, Runqing, Bian, Qi, Shao, Zhibin, Jing, Hongmei, Zhu, Lujun, Hou, Yuefei, Gao, Yu-Hang, Li, Shaojian, Zheng, Fawei, Zhang, Ping, Pan, Mojun, Liu, Junde, Qu, Gexing, Gu, Yadong, Zhang, Hao, Dong, Qinxin, Huang, Yifei, Yuan, Xiaoxia, He, Junbao, Li, Gang, Qian, Tian, Chen, Genfu, Li, Shao-Chun, Pan, Minghu, Xue, Qi-Kun
• Format: Article
• Language: English
• Subjects: 147/138; 147/143; 639/766/119/1003; 639/766/119/2792; Electrons; First principles; Heterostructures; Humanities and Social Sciences; Layered materials; Mixtures; multidisciplinary; P waves; Science; Science (multidisciplinary); Spectroscopy; Superconductivity; Symmetry; Topology
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-023-42781-7

The search for topological superconductivity (TSC) is currently an exciting pursuit, since non-trivial topological superconducting phases could host exotic Majorana modes. However, the difficulty in fabricating proximity-induced TSC heterostructures, the sensitivity to disorder and stringent topological restrictions of intrinsic TSC place serious limitations and formidable challenges on the materials and related applications. Here, we report a new type of intrinsic TSC, namely intrinsic surface topological superconductivity (IS-TSC) and demonstrate it in layered AuSn 4 with T c of 2.4 K. Different in-plane and out-of-plane upper critical fields reflect a two-dimensional (2D) character of superconductivity. The two-fold symmetric angular dependences of both magneto-transport and the zero-bias conductance peak (ZBCP) in point-contact spectroscopy (PCS) in the superconducting regime indicate an unconventional pairing symmetry of AuSn 4 . The superconducting gap and surface multi-bands with Rashba splitting at the Fermi level ( E F ), in conjunction with first-principle calculations, strongly suggest that 2D unconventional SC in AuSn 4 originates from the mixture of p- wave surface and s- wave bulk contributions, which leads to a two-fold symmetric superconductivity. Our results provide an exciting paradigm to realize TSC via Rashba effect on surface superconducting bands in layered materials. The authors study the layered superconductor AuSn 4 ( T c  = 2.4 K) and reveal a two-fold symmetric angular dependence, consistent with unconventional pairing. They argue that the two-fold symmetry results from the Rashba-driven mixture of p -wave surface and s -wave bulk contributions.