Tuning from ferroelectric topological insulator to superconductor in (Pb,Sn,In)Te

ORAL  · Invited

Abstract

At low temperature, SnTe is both a ferroelectric and a topological crystalline insulator.  One can tune both the bulk insulating (and conducting surface) character and achieve a superconducting state, with a transition as high as 4.7 K, by partial substitution of Pb and In for Sn.  Our neutron scattering measurements confirm the soft zone-center transverse-optical phonon in superconducting (Pb,Sn,In)Te, making it similar to the case of doped SrTiO3.  Intriguingly, in the case of Pb0.5Sn0.5Te, superconductivity is only observed when sufficient In is substituted to push the system into an electron-doped regime, where the normal-state resistivity is non-metallic and larger than that for SrTiO3 when doped into its regime of superconductivity.  This unexpected combination of features is in need of an explanation.

*Work at BNL supported by Office of Basic Energy Sciences, US DOE, under Contract No. DE-SC0012704.

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Publication: 1. R. D. Zhong et al., Phys. Rev. B 90, 020505(R) (2014).
2. R. D. Zhong et al., Crystals 7, 55 (2017).
3. A.Sapkota et al., Phys. Rev. B 102, 104511 (2020).

Presenters

  • John M Tranquada

    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
    • Brookhaven National Laboratory

Authors

  • John M Tranquada

    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA
    • Brookhaven National Laboratory

  • Genda Gu

    • Brookhaven National Laboratory
    • Condensed Matter Physics and Materials Science Department, Brookhaven National Laboratory, Upton, NY 11973, USA

  • Yangmu Li

    • Brookhaven National Laboratory

  • Aashish Sapkota

    • Ames Laboratory/Iowa State University
    • Ames Laboratory

  • Jinsheng Wen

    • Nanjing University

  • Ruidan Zhong

    • Shanghai Jiao Tong Univ