Terahertz conductivity of superconducting Beta-tungsten thin films

ORAL

Abstract

Ultrathin films of β-tungsten host superconductivity with strong spin-orbit coupling (SOC). This non-equilibrium phase of tungsten has attracted considerable attention in recent years for spintronic applications due to its giant spin Hall effect and the potential promise of exotic superconductivity. After more than 60 years of its discovery, the superconductivity in this material is still not well understood. We investigate the superconducting order in β-Tunsgten using high precision time-domain THz transmission spectroscopy. Superconductivity is exhibited below 4.2 K for 70 nm film and the transition temperature reduces with increasing thickness. We study the frequency response of the complex conductivity of a thin film with a Tc of 4.2 K. In the superconducting state down to 1.6 K, the superfluid spectral weight developed is much less than the expected spectral weight for a BCS-type superconductor. This anomalous spectral weight is a possible indication of unconventional superconductivity in this system. The magnetic field response of the optical conductivity that can give additional information about the superconducting order parameter of this system, is currently under investigation.

*Work at MSU was supported through the Office of Naval Research – Grant No. N00014-17-1-2794

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Presenters

  • Prashant Chauhan

    • Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218
    • Johns Hopkins University

Authors

  • Peter Armitage

    • Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218
    • Johns Hopkins University
    • Institute of Quantum Matter, Department of Physics and Astronomy, Johns Hopkins University

  • Prashant Chauhan

    • Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218
    • Johns Hopkins University

  • Ramesh Budhani

    • Department of Physics, Morgan State University, 1700E Cold Spring Lane, Baltimore MD -21251
    • Morgan State University, Baltimore, USA
    • Morgan State Univ