Nano-engineering of electron correlation in oxide superlattices

TL;DR

This study demonstrates how the electronic correlation properties of SrVO3 in oxide superlattices can be precisely tuned by adjusting layer thickness, revealing a transition from insulating to metallic states.

Contribution

It introduces a method to control electron correlation in oxide superlattices through layer thickness variation, enhancing the tunability of correlated oxides.

Findings

Spectral function of SrVO3 can be tuned from Mott-Hubbard insulator to metal.

Interlayer coupling enhances the effects of dimensionality on correlations.

Spectroscopic techniques reveal changes in electronic states with layer thickness.

Abstract

Oxide heterostructures and superlattices have attracted a great deal of attention in recent years owing to the rich exotic properties encountered at their interfaces. We focus on the potential of tunable correlated oxides by investigating the spectral function of the prototypical correlated metal SrVO3, using soft x-ray absorption spectroscopy (XAS) and resonant inelastic soft x-ray scattering (RIXS) to access both unoccupied and occupied electronic states, respectively. We demonstrate a remarkable level of tunability in the spectral function of SrVO3 by varying its thickness within the SrVO3/SrTiO3 superlattice, showing that the effects of electron correlation can be tuned from dominating the energy spectrum in a strongly correlated Mott-Hubbard insulator, towards a correlated metal. We show that the effects of dimensionality on the correlated properties of SrVO3 are augmented by interlayer coupling, yielding a highly flexible correlated oxide that may be readily married with other oxide systems.