Critical Temperature Enhancement by Biaxial Compressive Strain in FeSe_(0.5)Te_(0.5) Thin Finns

摘要

High-purity epitaxial FeSe_(0.5)Te_(0.5) thin films with different thicknesses were grown by pulsed laser ablation on different substrates. By varying the film thickness, T_c values of up to 21 K 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 T_c. The latter result indicates the important role of the compressive strain in enhancing T_c: the compressive strain derives from the Volmer-Weber growth of the films. The critical temperature is also related to both the Fe-(Se, Te) bond length and angle, suggesting the possibility of further enhancement.