Superconductivity in iron telluride thin films under tensile stress

TL;DR

This study demonstrates that applying tensile stress to FeTe thin films induces superconductivity at 13 K, with structural and magnetic changes linked to the transition temperature, revealing new pathways for enhancing superconductivity in iron-based materials.

Contribution

It introduces a method to induce superconductivity in FeTe via tensile stress in thin films, showing structural and magnetic correlations with transition temperature.

Findings

Superconductivity at 13 K was achieved in FeTe thin films under tensile stress.

Tensile stress causes softening of magnetic and structural phase transitions.

Universal in-plane extension and out-of-plane contraction observed in all FeTe films.

Abstract

By realizing in thin films a tensile stress state, superconductivity of 13 K was introduced into FeTe, an non-superconducting parent compound of the iron pnictides and chalcogenides, with transition temperature higher than that of its superconducting isostructural counterpart FeSe. For these tensile stressed films, the superconductivity is accompanied by the softening of the first-order magnetic and structural phase transition; and also, the in-plane extension and out-of-plane contraction are universal in all FeTe films independent of sign of lattice mismatch, either positive or negative. Moreover, the correlations were found exist between the transition temperatures and the tetrahedra bond angles in these thin films.