1School of Physical Science and Technology, ShanghaiTech University, Shanghai 201210, China 2Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Shanghai 201800, China 3University of Chinese Academy of Sciences, Beijing 100049, China 4Department of Materials Science and Engineering, Stanford University, Stanford, CA 94305, USA 5National Laboratory of Solid State Microstructures, College of Engineering and Applied Sciences, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, China 6State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China 7Frontier Science Center for Quantum Information, Beijing 100084, China 8Department of Physics, University of Oxford, Oxford, OX1 3PU, UK 9ShanghaiTech Laboratory for Topological Physics, Shanghai 201210, China
Abstract：Topological superconductors (TSCs) have been widely investigated in recent years due to their novel physics and ability to host Majorana fermions (MFs) which are key to topological quantum computation. Despite the great interest, only a few compounds have been proposed as candidates of intrinsic TSCs, such as iron-based superconductor FeSe$_{0.55}$Te$_{0.45}$ and 2M-WS$_{2}$. Among them, quasi-one-dimensional superconductor TaSe$_{3}$ possesses fascinating properties such as its simple stoichiometry, layered nature and chemical stability. Here, using scanning tunneling microscope/spectroscopy (STM/STS), we systematically investigate the topography and electronic structure of TaSe$_{3}$. Our STM/STS measurement reveals large atomically flat, defect-free surfaces suitable for the search of MF; electronic density of states consistent with our angle-resolved photoemission result and band-structure calculations, and a uniform superconducting gap with a typical size of $\sim $0.25 meV. Remarkably, additional edge states are observed in the vicinity of the terrace edge, suggesting they may have a topological origin. Our result proves the coexistence of superconductivity and topological electronic structure in TaSe$_{3}$, making it an intriguing platform to investigate topological superconductivity.
2021, Vol. 38 
