Signatures of two-gap superconductivity in epitaxial La(Pt<i><sub>x</sub></i>Si<sub>1-<i>x</i></sub>)<sub>2</sub> films

ORAL

Abstract

Symmetry plays an important role in superconductivity. In noncentrosymmetric superconductors, the pairing state might become a mixture of spin-singlet and spin-triplet components due to the anti-symmetric spin-orbit coupling (ASOC), which is “protected” by the lack of an inversion center. This mixing can further lead to two-gap physics. We investigated the transport properties of various La(PtxSi1-x)2 thin films grown by molecular beam epitaxy (MBE), where the inversion symmetry and spin-orbit coupling strength are tunable by varying the Pt concentration x. For certain x, magnetoresistance shows a two-step transition at finite temperatures below Tc, and the upper critical field is well described by a two-band model. Furthermore, the current-voltage characteristics, along with the differential resistance measurements, reveal a two-gap structure in magnetic fields up to 1 T. These observations indicate the multi-gap superconductivity in La(PtxSi1-x)2 films.

*This work was supported by UT Dallas research enhancement funds, National Science Foundation (NSF-DMR 1700137), Office of Naval Research (N00014-16-1-2657), and Center for Integrated Quantum Materials (DMR-1231319).

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Presenters

  • Jian Liao

    • Department of Physics, University of Texas at Dallas, Richardson, TX, 75080

Authors

  • Jian Liao

    • Department of Physics, University of Texas at Dallas, Richardson, TX, 75080

  • Yunbo Ou

    • Dept. Of Physics, Plasma Science and Fusion Center and Francis Bitter Magnet Lab, Massachusetts Institute of Technology
    • MIT
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory, MIT, Cambridge, MA, 02139

  • Jagadeesh Moodera

    • Dept. Of Physics, Plasma Science and Fusion Center and Francis Bitter Magnet Lab, Massachusetts Institute of Technology
    • MIT
    • Department of Physics, Massachusetts Institute of Technology
    • Massachusetts Institute of Technology
    • Department of Physics, Plasma Science and Fusion Center, and Francis Bitter Magnet Lab, Massachusetts Institute of Technology
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory, MIT
    • Plasma Science and Fusion Center, and Francis Bitter Magnet Laboratory, and Department of Physics, MIT
    • Francis Bitter Magnet Laboratory and Plasma Science and Fusion Center, MASSACHUSETTS INSTITUTE OF TECHNOLOGY
    • Plasma Science and Fusion Center and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology
    • Physics, Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology
    • Department of Physics, MIT, Cambridge, MA, 02139

  • Xiaoyan Shi

    • Department of Physics, University of Texas at Dallas
    • Department of Physics, University of Texas at Dallas, Richardson, TX, 75080