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Metallization and loss of surface magnetic ordering in FeSi under high pressure

ORAL

Abstract

Single-crystalline FeSi samples with a conducting surface state were studied under high pressure and magnetic field by means of electrical resistance measurements to explore how the bulk semiconducting state and the surface state are tuned by the application of pressure. We found that the energy gap associated with the semiconducting bulk phase begins to close abruptly at a critical pressure of ∼10 GPa and the bulk material becomes metallic with no obvious sign of any emergent phases or non-Fermi liquid behavior in temperature dependent electrical resistance in the neighborhood of the critical pressure above 3 K. Moreover, the metallic phase appears to remain at near-ambient pressure upon release of the pressure. Interestingly, the hysteresis in the electrical resistance vs magnetic field curve associated with the magnetically ordered conducting surface state decreases with pressure and vanishes at the critical pressure, while the slope of the electrical resistance vs magnetic field curve, which has a negative value for pressure below the critical pressure, decreases in magnitude with pressure and changes sign at the critical pressure. Thus, the conducting surface state and the corresponding two-dimensional magnetic order collapse at the critical pressure where the energy gap of the bulk material starts to close abruptly, revealing the connection between the conducting surface state and the semiconducting bulk state in FeSi.

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Presenters

  • Yuhang Deng

    University of California, San Diego, Department of Physics, University of California, San Diego, CA 92093, USA

Authors

  • Yuhang Deng

    University of California, San Diego, Department of Physics, University of California, San Diego, CA 92093, USA

  • Farhad Z Taraporevala

    University of California, San Diego

  • Haozhe Wang

    Michigan State University

  • Eric Lee-Wong

    University of California, San Diego, Department of Physics, University of California, San Diego, CA 92093, USA

  • Camilla M Moir

    University of California, San Diego, Department of Physics, University of California, San Diego, CA 92093, USA

  • Jinhyuk Lim

    University of Florida, Department of Physics, Eastern Illinois University

  • Shubham Sinha

    University of Florida, Department of Physics, University of Florida

  • Weiwei Xie

    Michigan State University

  • James J Hamlin

    University of Florida, Department of Physics, University of Florida

  • Yogesh K Vohra

    University of Alabama at Birmingham, Department of Physics, University of Alabama at Birmingham

  • M. Brian Maple

    University of California, San Diego, University of California San Diego, Department of Physics, University of California, San Diego, CA 92093, USA