Tuning the metal-insulator transition in epitaxial SrVO3 films by uniaxial strain

TL;DR

This study demonstrates how uniaxial strain via helium ion irradiation can effectively tune the metal-insulator transition in epitaxial SrVO3 films, highlighting the role of electron-electron interactions over disorder effects.

Contribution

It introduces a novel method to control the MIT in SrVO3 films by expanding the out-of-plane lattice constant without altering in-plane parameters, supported by experimental and theoretical analysis.

Findings

MIT observed with increased ion fluence

Transition driven mainly by electron-electron interactions

Theoretical calculations confirm bandwidth reduction

Abstract

Understanding of the metal-insulator transition (MIT) in correlated transition-metal oxides is a fascinating topic in condensed matter physics and a precise control of such transitions plays a key role in developing novel electronic devices. Here we report an effective tuning of the MIT in epitaxial SrVO3 (SVO) films by expanding the out-of-plane lattice constant without changing in-plane lattice parameters, through helium ion irradiation. Upon increase of the ion fluence, we observe a MIT with a crossover from metallic to insulating state in SVO films. A combination of transport and magnetoresistance measurements in SVO at low temperatures reveals that the observed MIT is mainly ascribed to electron-electron interactions rather than disorder-induced localization. Moreover, these results are well supported by the combination of density functional theory and dynamical mean field theory (DFT+DMFT) calculations, further confirming the decrease of the bandwidth and the enhanced electron-electron interactions resulting from the expansion of out-of-plane lattice constant. These findings provide new insights into the understanding of MIT in correlated oxides and perspectives for the design of unexpected functional devices based on strongly correlated electrons.