Toward an artificial Mott insulator: Correlations in confined, high-density electron liquids in SrTiO3

TL;DR

This study explores how strong electron correlations in confined, high-density SrTiO3 quantum wells lead to an insulating state, revealing the emergence of correlation-driven insulators at densities below one electron per site.

Contribution

It demonstrates the onset of correlation-induced insulating behavior in high-density, confined electron liquids in SrTiO3, highlighting the role of short-range Coulomb interactions and disorder.

Findings

Insulating state emerges at a critical density below one electron per site.

Short-range Coulomb interactions influence transport properties.

Disorder impacts the insulating phase.

Abstract

We investigate correlation physics in high-density, two-dimensional electron liquids that reside in narrow SrTiO3 quantum wells. The quantum wells are remotely doped via an interfacial polar discontinuity and the three-dimensional (3D) carrier density is modulated by changing the width of the quantum well. It is shown that even at 3D densities well below one electron per site, short-range Coulomb interactions become apparent in transport, and an insulating state emerges at a critical density. We also discuss the role of disorder in the insulating state.