Reversible tuning of magnetic order and intrinsic superconductivity in strained FeTe thin films via stoichiometry control

TL;DR

This study demonstrates that precise stoichiometry control in strained FeTe thin films can reversibly suppress magnetic order and induce intrinsic superconductivity around 10 K, providing new insights into iron chalcogenide physics.

Contribution

It shows that stoichiometric tuning alone can induce intrinsic superconductivity in FeTe thin films without complex interfacial effects.

Findings

Suppression of antiferromagnetic order through Fe impurity reduction

Induction of superconductivity at ~10 K

Reversible tuning of magnetic and superconducting states

Abstract

FeTe is a prototypical parent compound of iron-based superconductors. While bulk FeTe is non-superconducting with a long-range bicollinear antiferromagnetic order, superconductivity has been achieved in thin films. However, the approaches usually involve complex oxygen incorporation or interfacial effects, the microscopic mechanisms of which remain elusive. Here, we prepare high-purity, bare FeTe thin films on SrTiO3 and investigate their magnetic and superconducting states combining both microscopic and macroscopic characterizations. By reducing the interstitial Fe impurities, we successfully suppress the long-range antiferromagnetic order, enhance the quasiparticle coherence and induce superconductivity at ~10 K. Moreover, this process is readily reversible by tuning the Fe concentration. Our findings reveal that precise stoichiometric control is sufficient to induce intrinsic superconductivity in strained FeTe thin films. This work provides insights into the competition between magnetism and superconductivity in iron chalcogenides, and supplies a robust pathway for developing stable, high-purity superconducting FeTe films.