FeTe$_{1-x}$Se$_{x}$ monolayer films: towards the realization of high-temperature connate topological superconductivity

TL;DR

This study investigates FeTe$_{1-x}$Se$_{x}$ monolayer films, revealing their potential as high-temperature topological superconductors with intrinsic band topology and superconductivity, through ARPES experiments.

Contribution

It provides experimental evidence that FeTe$_{1-x}$Se$_{x}$ monolayers are high-temperature topological superconductors with integrated band topology and superconductivity.

Findings

Superconductivity is robust despite band variations.

Band gap decreases towards band inversion.

Evidence of nontrivial topological state.

Abstract

We performed angle-resolved photoemission spectroscopy studies on a series of FeTe$_{1-x}$Se$_{x}$ monolayer films grown on SrTiO$_{3}$. The superconductivity of the films is robust and rather insensitive to the variations of the band position and effective mass caused by the substitution of Se by Te. However, the band gap between the electron- and hole-like bands at the Brillouin zone center decreases towards band inversion and parity exchange, which drive the system to a nontrivial topological state predicted by theoretical calculations. Our results provide a clear experimental indication that the FeTe$_{1-x}$Se$_{x}$ monolayer materials are high-temperature connate topological superconductors in which band topology and superconductivity are integrated intrinsically.