Observation of topological superconductivity on the surface of iron-based superconductor

ORAL

Abstract

Topological superconductors, whose edge hosts Majorana bound states or Majorana fermions that obey non-Abelian statistics, can be used for low-decoherence quantum computations. Most of the proposed topological superconductors are realized with spin-helical states through proximity effect to BCS superconductors. However, such approaches are difficult for further studies and applications because of the low transition temperatures and complicated hetero-structures. Here by using high-resolution spin-resolved and angle-resolved photoelectron spectroscopy, we discover that the iron-based superconductor FeTe1-xSex (x = 0.45, Tc = 14.5 K) hosts Dirac-cone type spin-helical surface states at Fermi level, which open an s-wave SC gap below Tc. Our study proves that the surface states of FeTe0.55Se0.45 are 2D topologically superconducting, and thus provides a simple and possibly high-Tc platform for realizing Majorana fermions.

–

Presenters

  • Peng Zhang

    Institute for Solid State Physics, University of Tokyo

Authors

  • Peng Zhang

    Institute for Solid State Physics, University of Tokyo

  • Koichiro Yaji

    Institute for Solid State Physics, University of Tokyo

  • Takahiro Hashimoto

    Institute for Solid State Physics, University of Tokyo

  • Yuichi Ota

    Institute for Solid State Physics, University of Tokyo

  • Takeshi Kondo

    Institute for Solid State Physics, University of Tokyo

  • Kozo Okazaki

    Institute for Solid State Physics, University of Tokyo

  • Zhijun Wang

    Physics, Princeton University, Princeton University, Department of Physics, Princeton University, Physics, Princeton

  • Jinsheng Wen

    National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing Univ, Department of Physics, Nanjing University, Nanjing University

  • Genda Gu

    Brookhaven National Laboratory, Brookhaven National Labs, Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Condensed Matter Physics and Material Science Department, Brookhaven National Laboratory, Condensed Matter &materials Science, Brookhaven Natl Lab, Brookhaven Natl Lab, Condensed Matter Physics and Materials Science, Brookhaven National Laboratory, Brookhaven Natl. Lab, Brookhaven National Lab, Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, brookhaven national laboratory

  • Hong Ding

    Insititute of Physics, Chinese Academy of Scienes (CAS), Institute of Physics, Chinese Academy of Sciences, Institute of physics, Chinese Academy of Sciences

  • Shik Shin

    Institute for Solid State Physics, University of Tokyo