Enhanced Seebeck effect in ion-gated FeSe

ORAL

Abstract

The reduction of the dimensionality leads to the manifestation of quantum phenomena and the development of electronic correlation. Such low dimensional effects often become even more pronounced in nano-scale materials including exfoliated atomic layers and their hetero structures, triggering the emergence of the novel electronic, optical, and magnetic properties. Here we report the thermoelectric effect of FeSe ultrathin films with an electric double layer configuration, which allows us to control not only the carrier density but also the film thickness down to monolayer [J. Shiogai et al., Nature Phys. 12, 42 (2016)]. By utilizing a chemical etching induced by applying a large gate bias, the thickness of thin films is reduced in a layer-by-layer manner. Accompanying the emergence of the high-Tc superconductivity, the ionic liquid gating on FeSe thin films induces the anomalous enhancement of the Seebeck effect. We will discuss the thickness and the temperature dependence of the thermoelectric properties in FeSe thin films in detail.

*This work was supported by JSPS KAKENHI Grant Numbers JP25000003, JP16H00923 (SATL), JP16H06345, JP17H02928, JP17K19060.

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Presenters

  • Sunao Shimizu

    • RIKEN

Authors

  • Sunao Shimizu

    • RIKEN

  • Shiogai Junichi

    • Tohoku University

  • Nayuta Takemori

    • RIKEN
    • Research Institute for Interdisciplinary Science, Okayama University

  • Shiro Sakai

    • RIKEN
    • Center for Emergent Matter Science, RIKEN
    • University of Tokyo and RIKEN CEMS

  • Hiroaki Ikeda

    • Ritsumeikan University

  • Ryotaro Arita

    • RIKEN
    • RIKEN Center for Emergent Matter Science
    • Department of Applied Physics and Quantum-Phase Electronics Center, University of Tokyo
    • University of Tokyo
    • University of Tokyo and RIKEN CEMS

  • Tsutomu Nojima

    • Tohoku University
    • Institute for Materials Research, Tohoku University

  • Atsushi Tsukazaki

    • Tohoku University
    • Institute for Materials Research, Tohoku University, Sendai 980-8577, Japan
    • IMR Tohoku University
    • IMR, Tohoku Univ.
    • Institute for Materials Research, Tohoku University

  • Yoshihiro Iwasa

    • Department of Applied Physics, The University of Tokyo
    • University of Tokyo
    • Department of applied physics, University of Tokyo
    • Department of Applied Physics, University of Tokyo
    • Quantum-Phase Electronics Center and Department of Applied Physics, University of Tokyo