Bandwidth Control and Symmetry Breaking in a Mott-Hubbard Correlated Metal

TL;DR

This paper demonstrates how lattice engineering via strain can control electron correlation strength and symmetry breaking in a Mott-Hubbard system, specifically in SrVO3, enabling potential device applications.

Contribution

It introduces a method to tune correlation strength by adjusting orbital overlap through strain, revealing how bandwidth control influences electronic structure and Mott transition.

Findings

Strain modifies orbital occupancy and degeneracy in SrVO3.

High tensile strain induces a Mott insulating state.

Spectral weight redistribution aligns with theoretical predictions.

Abstract

In Mott materials strong electron correlation yields a spectrum of complex electronic structures. Recent synthesis advancements open realistic opportunities for harnessing Mott physics to design transformative devices. However, a major bottleneck in realizing such devices remains the lack of control over the electron correlation strength. This stems from the complexity of the electronic structure, which often veils the basic mechanisms underlying the correlation strength. Here, we present control of the correlation strength by tuning the degree of orbital overlap using picometer-scale lattice engineering. We illustrate how bandwidth control and concurrent symmetry breaking can govern the electronic structure of a correlated $SrVO_3$ model system. We show how tensile and compressive biaxial strain oppositely affect the $SrVO_3$ in-plane and out-of-plane orbital occupancy, resulting in the partial alleviation of the orbital degeneracy. We derive and explain the spectral weight redistribution under strain and illustrate how high tensile strain drives the system towards a Mott insulating state. Implementation of such concepts will drive correlated electron phenomena closer towards new solid state devices and circuits. These findings therefore pave the way for understanding and controlling electron correlation in a broad range of functional materials, driving this powerful resource for novel electronics closer towards practical realization.