Observation of topologically protected surface states in a Bi-Pd superconductor

ORAL

Abstract

A layered Bi-Pd superconductor is investigated by spin- and angle-resolved photoemission spectroscopy. Beside the spin-degenerate bulk bands, several spin-polarized surface bands, some of which crossing the Fermi level, are clearly observed. These surface states are evaluated to be topologically protected, based on the Z$_{2}$ invariant analysis in analogy to 3-dimensional strong topological insulators. It indicates that this material is likely to be a topological superconductor realized without any carrier doping or applying pressure.

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Authors

  • Masato Sakano

    • Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo

  • Kenjiro Okawa

    • Materials and Structures Laboratory, Tokyo Institute of Technology

  • Manabu Kanou

    • Materials and Structures Laboratory, Tokyo Institute of Technology

  • Haruhiko Sanjo

    • Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo

  • Taichi Okuda

    • Hiroshima Synchrotron Radiation Center, Hiroshima University

  • Takao Sasagawa

    • Materials and Structures Laboratory, Tokyo Institute of Technology

  • Kyoko Ishizaka

    • Quantum-Phase Electronics Center (QPEC) and Department of Applied Physics, The University of Tokyo