Superconductivity Induced in Iron Telluride Films by Low Temperature Oxygen Incorporation

TL;DR

This study demonstrates that low temperature oxygen incorporation can induce superconductivity in non-superconducting FeTe films by altering their valence state, offering a new doping method for iron-based superconductors.

Contribution

It reveals a reversible oxygen doping process that induces superconductivity in FeTe films and shows how oxygen changes the Fe valence state, differing from typical FeTeSe systems.

Findings

Oxygen doping induces superconductivity in FeTe films.

Oxygen incorporation changes Fe valence from 2+ to mainly 3+.

The process is reversible and allows in-situ doping experiments.

Abstract

We report superconductivity induced in films of the non-superconducting, antiferromagnetic parent material FeTe by low temperature oxygen incorporation in a reversible manner. X-ray absorption shows that oxygen doping changes the nominal Fe valence state from 2+ in the non-superconducting state to mainly 3+ in the superconducting state. Thus superconductivity in O doped FeTe occurs in a quite different charge and strain state than the more common FeTe$_{1-x}$Se$_x$. This work also suggests a convenient path for conducting doping experiments in-situ with many measurement techniques.