Tc=21K in epitaxial FeSe0.5Te0.5 thin films with biaxial compressive strain

TL;DR

This study demonstrates that epitaxial FeSe0.5Te0.5 thin films with biaxial compressive strain can achieve a superconducting transition temperature up to 21K, surpassing bulk values, through strain and structural modifications.

Contribution

It reveals the relationship between strain, structural parameters, and Tc in FeSe0.5Te0.5 thin films, highlighting strain engineering as a route to enhance superconductivity.

Findings

Tc up to 21K observed in thin films

Linear relation between a axis and Tc

Strain influences bond length and angle

Abstract

High purity epitaxial FeSe0.5Te0.5 thin films with different thickness were grown by Pulsed Laser Ablation on different substrates. By varying the film thickness, Tc up to 21K were observed, significantly larger than the bulk value. Structural analyses indicated that the a axis changes significantly with the film thickness and is linearly related to the Tc. The latter result indicates the important role of the compressive strain in enhancing Tc. Tc is also related to both the Fe-(Se,Te) bond length and angle, suggesting the possibility of further enhancement.