Interface induced high temperature superconductivity in single unit-cell FeSe films on SrTiO3(110)

TL;DR

This study demonstrates high temperature superconductivity in single-unit-cell FeSe films on SrTiO3(110), highlighting the role of interface effects like charge transfer and electron-phonon coupling in enhancing superconductivity.

Contribution

It reports the realization of high Tc superconductivity in FeSe/STO(110) films and explores how interface effects influence this phenomenon, expanding understanding beyond the well-studied STO(001) surface.

Findings

Superconducting gap of 17 meV observed via STM.

Onset Tc of 31.6 K with a critical field of 30.2 T.

External electric field slightly increases Tc.

Abstract

We report high temperature superconductivity in one unit-cell (1-UC) FeSe films grown on STO(110) substrate by molecular beam epitaxy. By in-situ scanning tunneling spectroscopy measurement, we observed a superconducting gap as large as 17 meV. Transport measurements on 1-UC FeSe/STO(110) capped with FeTe layers reveal superconductivity with an onset TC of 31.6 K and an upper critical magnetic field of 30.2 T. We also find that the TC can be further increased by an external electric field, but the effect is smaller than that on STO(001) substrate. The study points out the important roles of interface related charge transfer and electron-phonon coupling in the high temperature superconductivity of FeSe/STO.