Observation of topological transition in high-T$_{c}$ superconductor FeTe$_{1-x}$Se$_{x}$/SrTiO$_{3}$(001) monolayers

TL;DR

This study directly observes a topological transition in high-temperature superconductor monolayers, revealing edge states and providing a promising platform for high-temperature Majorana state realization.

Contribution

It demonstrates the topological transition in FeTe$_{1-x}$Se$_{x}$/SrTiO$_{3}$ monolayers using ARPES and STM, offering a tunable high-temperature platform for Majorana states.

Findings

Observation of topological transition near the Fermi level.

Detection of edge states via scanning tunneling spectroscopy.

Theoretical calculations support experimental results.

Abstract

Superconductors with topological surface or edge states have been intensively explored for the prospect of realizing Majorana bound states, which obey non-Abelian statistics and are crucial for topological quantum computation. The traditional routes for making topological insulator/superconductor and semiconductor/superconductor heterostructures suffer fabrication difficulties and can only work at low temperature. Here, we use angle-resolved photoemission spectroscopy to directly observe the evolution of a topological transition of band structure nearby the Fermi level in two-dimensional high-T$_{c}$ superconductor FeTe$_{1-x}$Se$_{x}$/SrTiO$_{3}$(001) monolayers, fully consistent with our theoretical calculations. Furthermore, evidence of edge states is revealed by scanning tunneling spectroscopy with assistance of theoretical calculations. Our study provides a simple and tunable platform for realizing and manipulating Majorana states at high temperature.