Control of band structure of FeSe single crystals via biaxial strain

TL;DR

This study demonstrates how applying in-plane biaxial strain to FeSe single crystals systematically alters their band structure, affecting structural and superconducting transition temperatures and carrier densities.

Contribution

It introduces a method to control the band structure of FeSe single crystals through biaxial strain via substrate thermal expansion differences.

Findings

Structural and superconducting transition temperatures vary with strain.

Carrier densities of electrons and holes change systematically with strain.

Band structure control is achieved in single-crystalline FeSe.

Abstract

We performed systematic transport measurements on FeSe single crystals with applying in-plane biaxial strain $\varepsilon$ ranging from -0.96% to 0.23%. Biaxial strain was introduced by firmly gluing samples to various substrate materials with different thermal expansion. With increasing $\varepsilon$, structural and superconducting transition temperatures monotonically increased and decreased, respectively. We analyzed magneto-transport results using a compensated three-carrier model. The evaluated densities of hole and electron carriers systematically changed with strain. This indicates that we succeeded in controlling the band structure of single-crystalline FeSe.