STM study of impurity states in topological superconducting candidates Li(Fe,Co)As and PbTaSe2

ORAL

Abstract

Introducing impurities, both magnetic and nonmagnetic, into superconducting systems via surface or bulk chemical substitution can both provide a wealth of information about the underlying system, as well as manipulate some of its crucial properties. Here, we use low temperature scanning tunnelling microscopy to study vortex core and impurity states in topological superconductor candidates Li(Fe,Co)As and PbTaSe2 at 0.4K. We perform a systematic study in the Li(Fe,Co)As system of eight Co concentrations, spanning its entire superconducting phase diagram. Using a superconducting tip, we explore the impurity effects on the topological surface states as well as bulk superconductivity in PbTaSe2. Our results not only provides strong constraints on their superconducting order parameters, but also sheds light on the interplay of magnetism and topological superconductivity.

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Presenters

  • Songtian Sonia Zhang

    Department of Physics, Princeton University, Princeton University

Authors

  • Songtian Sonia Zhang

    Department of Physics, Princeton University, Princeton University

  • Jiaxin Yin

    Department of Physics, Princeton University, Princeton University

  • Genfu Chen

    Institute of Physics, Chinese Academy of Sciences, institute of physics chinese academy of sciences

  • Guoqing Chang

    Department of Physics, Princeton University, Princeton University, Physics, Princeton U.

  • Tay-Rong Chang

    National Cheng Kung University, Physics, National Cheng Chung University, Physics, National Cheng Kung University, Tainan, 701, Taiwan, Department of Physics, National Cheng Kung University, Physics, National Tsing Hua University, Physics, National Cheng Kung University

  • Kun Jiang

    Department of Physics, Boston College, Boston College, Physics, Boston College

  • Changqing Jin

    Institute of Physics, Chinese Academy of Sciences, Chinese Academy of Sciences

  • Hsin Lin

    Academia Sinica, Institute of Physics, Academia Sinica, Physics, Academia Sinica, Taipei 11529, Taiwan, Institute of Physics, Academia Sinica, Taipei 11529, Taiwan, Physics, Academia Sinica, Department of Physics, National University of Singapore, National University of Singapore, Academia Sinica, Taipei, Taiwan

  • Ziqiang Wang

    Department of Physics, Boston College, Boston College, Physics, Boston College

  • Raman Sankar

    Center for Condensed Matter Sciences, National Taiwan University, Center for Condensed Matter Science, National Taiwan University, Center of Condensed Matter Sciences, National Taiwan University, Institute of Physics, Academia Sinica, National Taiwan University, Physics, Academia Sinica, Taiwan

  • Zahid Hasan

    Department of Physics, Princeton University, Princeton University, Laboratory for Topological Quantum Matter & Advanced Spectroscopy, Princeton University, Physics, Princeton U.