Intrinsic surface p-wave superconductivity in layered AuSn4
Wenliang Zhu, Rui Song, Jierui Huang, Qiwei Wang, Yuan Cao, Runqing Zhai, Qi Bian, Zhibin Shao, Hongmei Jing, Lujun Zhu, Yuefei Hou, Yuhang Gao, Shaojian Li, Fawei Zheng, Ping Zhang, Mojun Pan, Junde Liu, Gexing Qu, Yadong Gu, Hao Zhang, Qinxin Dong, Yifei Huang, Xiaoxia Yuan, Junbao He, Gang Li, Tian Qian, Genfu Chen, Shao‐Chun Li, Minghu Pan, Qi‐Kun Xue, Shao‐Chun Li, Minghu Pan, Minghu Pan, Qi‐Kun Xue
Abstract
Abstract 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.