Evidence for a conducting surface state in FeSi

ORAL

Abstract

Electrical transport measurements on high quality single crystals of FeSi show a crossover from semiconducting to metallic behavior at 19 K (Tc). This metallic temperature dependent resistivity points to a conducting surface ground state of FeSi, supported by the impact of surface-to-volume ratio on the resistivity of the sample, and the absence of features in specific heat at low temperature [1]. We further explore this surface state using high field magnetoresistance, high pressure, and magnetic field modulated microwave spectroscopy (MFMMS). Surprisingly, the surface sensitive MFMMS measurement of FeSi shows an anomaly near Tc with a signature typically associated with superconducting transitions. Based on the similarities in magnetoresistance between FeSi and the possible topological Kondo insulator SmB6, FeSi could be a possible topological insulator.

[1] Y. Fang, S. Ran, W. Xie, S. Wang, Y. Meng, and M. B. Maple, PNAS 117, 8558 (2019)

*Work at UCSD: US DOE, BES Grant DEFG02-04-ER46105, US NSF Grant No. DMR-1206553/1810310, and NNSA through US DOE Grant DE-NA0002909. Work at the National High Magnetic Field Laboratory: US NSF/DMR-1157490/1644779 and the State of Florida. Work at Center for High Pressure Science & Technology Advanced Research, China: NSFC grant No. 51871054.

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Presenters

  • Yuhang Deng

    • University of California, San Diego
    • UC San Diego

Authors

  • Yuhang Deng

    • University of California, San Diego
    • UC San Diego

  • Yuankan Fang

    • University of California, San Diego

  • Sheng Ran

    • University of California, San Diego

  • Weiwei Xie

    • Chemistry, Louisiana State University
    • Louisiana State University
    • Department of Chemistry, Louisiana State University
    • Louisiana State University, Baton Rouge

  • Shen Wang

    • University of California, San Diego

  • Shirley Meng

    • University of California, San Diego
    • Univeristy of California San Diego

  • Christian T Wolowiec

    • University of California, San Diego

  • Ivan Schuller

    • University of California, San Diego
    • Department of Physics, University of California San Diego
    • Center for Advanced Nanoscience, Department of Physics, University of California-San Diego

  • Hongbo Lou

    • Center for High Pressure Science & Technology Advanced Research

  • Shubin Li

    • Center for High Pressure Science & Technology Advanced Research

  • Qiaoshi Zeng

    • Center for High Pressure Science & Technology Advanced Research

  • John Singleton

    • National High Magnetic Field Lab, Los Alamos
    • Los Alamos National Laboratory
    • NHMFL, Los Alamos National Laboratory
    • National High Magnetic Field Laboratory, Los Alamos National Laboratory
    • NHMFL, Los Alamos National Lab
    • Los Alamos National Lab.

  • Alexander Breindel

    • University of California, San Diego

  • M Brian Maple

    • Department of Physics, University of California, San Diego
    • UCSD
    • University of California, San Diego
    • physics, University of Califormia, San Diego
    • Departement of Physics, University fo California, San Diego
    • Physics, University of California, San Diego