Superconductivity in Bi2-x Sbx Te3-y Sey (x = 1.0 and y = 2.0) under pressure

Tong He, Xiaofan Yang, Tomoya Taguchi, Lei Zhi, Takafumi Miyazaki, Kaya Kobayashi, Jun Akimitsu, Hirofumi Ishii, Yen Fa Liao, Hidenori Goto, Ritsuko Eguchi, Yoshihiro Kubozono

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    3 Citations (Scopus)

    Abstract

    The crystal structure of BiSbTeSe2 (Bi2-x Sb x Te3-y Se y (x = 1.0 and y = 2.0)) at 0-29 GPa is investigated through synchrotron x-ray diffraction (XRD) and two structural phase transitions are discovered. The stoichiometry of BiSbTeSe2 employed in this study is Bi1.19(4)Sb0.81(4)Te0.83(4)Se2.17(4), as determined from energy-dispersive x-ray spectroscopy. The sample demonstrated structural transitions, from a rhombohedral structure (space group no 166, R m) (phase I) to a monoclinic structure (space group no 12, C2/m) (phase II), and from phase II to a 9/10-fold monoclinic structure (space group no 12, C2/m) (phase III). The temperature dependence of resistance (R-T plot) exhibited a semiconducting behavior in a low pressure range and changed from semiconducting to metallic behavior with increasing pressure. Pressure-driven superconductivity is observed above 9.1 GPa in Bi1.19(4)Sb0.81(4)Te0.83(4)Se2.17(4). The pressure phase corresponds to phase II. The superconducting transition temperature, T c, increased with pressure. The maximum T c value is 8.3 K at 19.1 GPa. The magnetic field dependence of T c in phase II of Bi1.19(4)Sb0.81(4)Te0.83(4)Se2.17(4) is proceeded by a p-wave polar model, indicating topologically nontrivial superconductivity. In addition, the emergence of superconductivity and the change in superconducting behavior are closely associated with the structural transitions.

    Original languageEnglish
    Article number465702
    JournalJournal of Physics Condensed Matter
    Volume32
    Issue number46
    DOIs
    Publication statusPublished - Nov 4 2020

    Keywords

    • crystal structure
    • electrical resistance
    • p-wave
    • pressure-driven superconductivity
    • topological insulator

    ASJC Scopus subject areas

    • Materials Science(all)
    • Condensed Matter Physics

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