Uncovering an interplay among fermiology, superconductivity, and nematicity in FeSe by epitaxial strain

ORAL

Abstract

Central issues in iron-based superconductors are the origins of superconductivity and nematicity as well as their interplay. To investigate these issues, we utilize a sizable strain effect in FeSe thin films, where compressive strain drastically enhances Tc by 50%, while tensile strain kills the superconductivity and simultaneously enhances the nematicity. By angle-resolved photoemission spectroscopy, we experimentally observed a monotonic change in the energy overlap (ΔEh−e) between the hole and electron pockets in the normal state upon variation of in-plane lattice constant [1]. The change in ΔEh−e modifies the Fermi-surface volume, leading to a change in Tc. Furthermore, the strength of nematicity is also found to be characterized by ΔEh−e. These results suggest that the key to understanding the phase diagram is the fermiology and interactions linked to the semimetallic band overlap.
[1] G. N. Phan et al. Phys. Rev. B 95, 224507 (2017).

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Presenters

  • Giao Phan

    • Dept. of Physics, Tohoku Univ

Authors

  • Giao Phan

    • Dept. of Physics, Tohoku Univ

  • Kosuke Nakayama

    • Dept. Physics, Tohoku Univ.
    • Department of Physics, Tohoku University
    • Dept. of Physics, Tohoku Univ

  • Katsuaki Sugawara

    • Tohoku University
    • WPI Research Center, Advanced Institute for Materials Research, Tohoku University

  • Takafumi Sato

    • Dept. Physics, Tohoku Univ.
    • Department of Physics, Tohoku Univ
    • Physics, Tohoku University
    • Tohoku University
    • Dept. of Physics, Tohoku Univ

  • Takahiro Urata

    • Dept. of Physics, Tohoku Univ

  • Youichi Tanabe

    • Dept. of Physics, Tohoku Univ

  • Kasumi Tanigaki

    • Dept. of Physics, Tohoku Univ
    • Tohoku Univ

  • Fuyuki Nabeshima

    • Dept. of Basic Science, Univ. of Tokyo
    • Dept. of Basic Science, the University of Tokyo
    • Univ of Tokyo

  • Yoshinori Imai

    • Department of Physics, Tohoku University
    • Dept. of Basic Science, the University of Tokyo

  • Atsutaka Maeda

    • Dept. of Basic Science, Univ. of Tokyo
    • Dept. of Basic Science, the University of Tokyo
    • Univ of Tokyo

  • Takashi Takahashi

    • WPI-AIMR, Tohoku Univ.
    • WPI-Advanced Institute for Materials Research
    • Tohoku University
    • Dept. of Physics, Tohoku Univ