Intrinsic surface p-wave superconductivity in layered AuSn4

Wenliang Zhu; Rui Song; Jierui Huang; Qi-Wei Wang; Yuan Cao; Runqing Zhai; Qi Bian; Zhibin Shao; Hongmei Jing; Lujun Zhu; Yuefei Hou; Yu-Hang 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

doi:10.1038/s41467-023-42781-7

Intrinsic surface p-wave superconductivity in layered AuSn₄

Nat Commun. 2023 Nov 2;14(1):7012. doi: 10.1038/s41467-023-42781-7.

Authors

Wenliang Zhu^#¹, Rui Song^#², Jierui Huang^#³, Qi-Wei Wang^#⁴, Yuan Cao^#¹, Runqing Zhai¹, Qi Bian⁵, Zhibin Shao¹, Hongmei Jing¹, Lujun Zhu¹, Yuefei Hou⁶, Yu-Hang Gao⁴, Shaojian Li⁵, Fawei Zheng⁶, Ping Zhang^{7

8}, Mojun Pan³, Junde Liu³, Gexing Qu³, Yadong Gu³, Hao Zhang¹, Qinxin Dong³, Yifei Huang³, Xiaoxia Yuan⁹, Junbao He¹⁰, Gang Li^{3

11

12}, Tian Qian^{13

14

15}, Genfu Chen^{16

17

18}, Shao-Chun Li¹⁹, Minghu Pan^{20

21}, Qi-Kun Xue^{22

23

24}

Affiliations

¹ School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710119, China.
² Science and Technology on Surface Physics and Chemistry Laboratory, Mianyang, 621908, China.
³ Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, China.
⁴ National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
⁵ School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China.
⁶ Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China.
⁷ Institute of Applied Physics and Computational Mathematics, Beijing, 100088, China. zhang_ping@iapcm.ac.cn.
⁸ School of Physics and Physical Engineering, Qufu Normal University, Qufu, 273165, China. zhang_ping@iapcm.ac.cn.
⁹ Shaanxi Applied Physics and Chemistry Research Institute, Xi'an, 710061, China.
¹⁰ College of Physics and Electronic Engineering, Nanyang Normal University, Nanyang, 473061, China.
¹¹ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China.
¹² Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China.
¹³ Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, China. tqian@iphy.ac.cn.
¹⁴ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China. tqian@iphy.ac.cn.
¹⁵ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China. tqian@iphy.ac.cn.
¹⁶ Institute of Physics and Beijing National Laboratory for Condensed Matter Physics, Chinese Academy of Sciences, Beijing, 100190, China. gfchen@iphy.ac.cn.
¹⁷ School of Physical Sciences, University of Chinese Academy of Sciences, Beijing, 100190, China. gfchen@iphy.ac.cn.
¹⁸ Songshan Lake Materials Laboratory, Dongguan, Guangdong, 523808, China. gfchen@iphy.ac.cn.
¹⁹ National Laboratory of Solid State Microstructures, School of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China. scli@nju.edu.cn.
²⁰ School of Physics and Information Technology, Shaanxi Normal University, Xi'an, 710119, China. minghupan@snnu.edu.cn.
²¹ School of Physics, Huazhong University of Science and Technology, Wuhan, 430074, China. minghupan@snnu.edu.cn.
²² State Key Laboratory of Low-Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing, 100084, China. qkxue@mail.tsinghua.edu.cn.
²³ Beijing Academy of Quantum Information Sciences, Beijing, 100193, China. qkxue@mail.tsinghua.edu.cn.
²⁴ Department of Physics, Southern University of Science and Technology, Shenzhen, 518055, China. qkxue@mail.tsinghua.edu.cn.

^# Contributed equally.

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 AuSn₄ 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 AuSn₄. 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 AuSn₄ 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.