Enhancement of superconducting transition temperature in FeSe electric-double-layer transistor with multivalent ionic liquids

Tomoki Miyakawa, Junichi Shiogai, Sunao Shimizu, Michio Matsumoto, Yukihiro Ito, Takayuki Harada, Kohei Fujiwara, Tsutomu Nojima, Yoshimitsu Itoh, Takuzo Aida, Yoshihiro Iwasa, Atsushi Tsukazaki

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)

Abstract

We report on an enhancement of the superconducting transition temperature (Tc) of the FeSe-based electric-double-layer transistor (FeSe-EDLT) by applying the multivalent oligomeric ionic liquids (ILs). The IL composed of dimeric cation (divalent IL) enables a large amount of charge accumulation on the surface of the FeSe ultrathin film, resulting in inducing electron-rich conduction even in a rather thick 10 nm FeSe channel. The onset Tc in FeSe-EDLT with the divalent IL is enhanced to be approaching about 50 K at the thin limit, which is about 7 K higher than that in EDLT with conventional monovalent ILs. The enhancement of Tc is a pronounced effect of the application of the divalent IL, in addition to the large capacitance, supposing preferable interface formation of ILs driven by geometric and/or Coulombic effect. The present finding strongly indicates that multivalent ILs are powerful tools for controlling and improving physical properties of materials.

Original languageEnglish
Article number031801
JournalPhysical Review Materials
Volume2
Issue number3
DOIs
Publication statusPublished - 2018 Mar 26

ASJC Scopus subject areas

  • Materials Science(all)
  • Physics and Astronomy (miscellaneous)

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