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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.

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

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