Thermoelectric Effect in Ultrathin FeSe

ORAL

Abstract

The enhancement of the superconducting transition temperature Tc in monolayer FeSe/SrTiO3 has been a central issue in 2D materials research in the last few years. However, the experimental investigation of monolayer FeSe has been limited to STM, ARPES, and electrical resistivity measurements due to the sensitivity to the air. Here we report the thermoelectric measurements in ultrathin films of FeSe through the in-situ electrochemical etching technique. The thickness of the FeSe films is controllable in ionic liquid media and can be reduced to monolayer [J. Shiogai et al., Nature Phys. 12, 42 (2016)]. With thinning the thin film with 18 nm thickness, Tc was enhanced up to ~40 K, and the anomalous enhancement of the Seebeck coefficient was observed. The thickness and the temperature dependence of the thermoelectric properties in FeSe will be discussed in detail.

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Presenters

  • Sunao Shimizu

    RIKEN

Authors

  • Sunao Shimizu

    RIKEN

  • Shiogai Junichi

    Institute for Materials Reaserch, Tohoku University, Tohoku Univ, IMR, Tohoku University, Institute for Materials Research

  • Nayuta Takemori

    Okayama Univ

  • Shiro Sakai

    RIKEN

  • Hiroaki Ikeda

    Ritsumeikan Univ, Department of Physics, Ritsumeikan University

  • Ryotaro Arita

    RIKEN, RIKEN Center for Emergent Matter Science, CEMS, RIKEN, Center for Emergent Matter Science, RIKEN

  • Tsutomu Nojima

    Institute for Materials Reaserch, Tohoku University, Tohoku Univ, Tohoku University, Tohoku Univ.

  • Atsushi Tsukazaki

    Institute for Materials Reaserch, Tohoku University, Tohoku Univ, Institute for Materials Research, Tohoku University, IMR, Tohoku University, Institute for Materials Research, Tohoku University, Tohoku Univ.

  • Yoshihiro Iwasa

    Univ of Tokyo, Department of Applied Physics, The University of Tokyo, The University of Tokyo, University of Tokyo, The Univ. of Tokyo, the University of Tokyo, the Univ. of Tokyo, Univ. of Tokyo