Abstract
Among the recently discovered iron-based superconductors, ultrathin films of FeSe grown on SrTiO 3 substrates have uniquely evolved into a high-transition-temperature (T c) superconducting material. The mechanisms for the high-T c superconductivity are under debate, with the superconducting gap mainly characterized with in situ analysis for FeSe films grown by molecular beam epitaxy. Here, we investigate the high-T c superconductivity in ultrathin FeSe using an alternative top-down electrochemical etching technique in a three-terminal transistor configuration. In addition to the high-temperature superconductivity in FeSe on SrTiO 3 , the electrochemically etched ultrathin FeSe transistor on MgO also exhibits superconductivity around 40 K, implying that the application of an electric field effectively contributes to the high-T c superconductivity in ultrathin FeSe regardless of substrate material. Moreover, the observable critical thickness for the high-T c superconductivity is expanded up to 10 unit cells under an applied electric field and the insulator-superconductor transition is electrostatically controlled. The present demonstration implies that the modification of charge imbalance of holes and electrons by the electric-field effect plays a crucial role in inducing high-T c superconductivity in FeSe-based electric double-layer transistors.
Original language | English |
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Pages (from-to) | 42-46 |
Number of pages | 5 |
Journal | Nature Physics |
Volume | 12 |
Issue number | 1 |
DOIs | |
Publication status | Published - 2016 Jan 7 |
ASJC Scopus subject areas
- Physics and Astronomy(all)