Observation of pressure-induced superconductivity in WB<sub>2</sub>

ORAL

Abstract

High-pressure electrical resistivity measurements reveal that the mechanical deformation of ultra-hard WB2 during compression induces superconductivity above 50 GPa with a maximum superconducting critical temperature, Tc of 17 K at 90 GPa [1]. Upon further compression up to 190 GPa, the Tc gradually decreases to 14 K at a rate of -0.024 K/GPa. We investigate the presence of MgB2-like structural transition (hP3, space group 191, prototype AlB2) in WB2 under pressures, which might be responsible for the relatively high Tc superconductivity as recently found in MoB2 [2]. Synchrotron x-ray diffraction measurements up to 145 GPa at room temperature show that the ambient pressure hP12 structure (space group 194, prototype WB2) continues to persist to this pressure without any structural transition. Thus, these experimental results indicate the novel origin of the abrupt appearance of superconductivity in WB2 under pressures above 50 GPa. In the following talk, we show that electron-phonon mediated superconductivity in WB2 originates from the formation of metastable stacking faults and twin boundaries that exhibit a local structure resembling the MgB2 structure.

*Work on this project was supported by the U.S. Department of Energy (DOE) Basic Energy Sciences under Contract No. DE-SC-0020385. High-pressure equipment development at UF supported by DMR-1453752. HPXRD at the Advanced Photon Source was supported by the U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA) through the Chicago/DOE Alliance Center (CDAC).

–

Publication: [1] arXiv:2109.11521 [cond-mat.supr-con]. https://arxiv.org/abs/2109.11521
[2] arXiv:2105.13250 [cond-mat.supr-con]. https://arxiv.org/abs/2105.13250

Presenters

  • Jinhyuk Lim

    • Department of Physics, University of Florida
    • University of Florida

Authors

  • Jinhyuk Lim

    • Department of Physics, University of Florida
    • University of Florida

  • Ajinkya C Hire

    • Department of Materials Science and Engineering, University of Florida
    • University of Florida

  • Yundi Quan

    • Department of Physics, University of Florida
    • University of Florida

  • Jung S Kim

    • Department of Physics, University of Florida

  • Stephen R Xie

    • Department of Materials Science and Engineering, University of Florida
    • KBR Inc., Intelligent Systems Division, NASA Ames Research Center
    • University of Florida

  • Ravhi S Kumar

    • University of Illinois at Chicago
    • Department of Physics, University of Illinois at Chicago
    • University of Illinois Chicago

  • Dmitry Popov

    • HPCAT, X-ray Science Division, Argonne National Laboratory
    • High-pressure Collaborative Access Team, Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439
    • Argonne National Laboratory

  • Changyong Park

    • HPCAT, X-ray Science Division, Argonne National Laboratory
    • Argonne National Laboratory

  • Russell J Hemley

    • University of Illinois Chicago
    • University of Illinois at Chicago
    • George Washington Univ
    • Departments of Physics and Chemistry, University of Illinois at Chicago
    • Department of Physics, University of Illinois at Chicago, Chicago, IL 60607, USA; Department of Chemistry, University of Illinois at Chicago, Chicago, IL 60607, USA
    • Department of Physics, University of Illinois Chicago, Chicago, USA
    • University of Illinois at Chicago, USA

  • James J Hamlin

    • University of Florida
    • Department of Physics, University of Florida

  • Richard G. G Hennig

    • University of Florida
    • Department of Materials Science and Engineering, University of Florida
    • Department of Materials Science and Engineering, University of Florida, Gainesville, Florida 32611, United States

  • Peter J Hirschfeld

    • University of Florida
    • Department of Physics, University of Florida

  • Gregory R Stewart

    • Department of Physics, University of Florida
    • University of Florida