Surface vs. bulk Coulomb correlations in photoemission spectra of perovskites

TL;DR

This paper investigates how Coulomb correlations differ between surface and bulk regions in perovskite materials, using dynamical mean field theory to explain experimental photoemission spectra modifications.

Contribution

The study demonstrates that surface atoms exhibit stronger Coulomb correlation effects than bulk atoms due to reduced coordination, aligning with experimental observations.

Findings

Surface correlations are stronger than bulk correlations.

Reduced coordination at the surface enhances correlation effects.

Theoretical results agree with experimental spectra modifications.

Abstract

Recent photoemission spectra of the perovskite series Sr$_x$Ca$_{1-x}$VO$_3$ revealed strong modifications associated with surface contributions. To study the effect of Coulomb correlations in the bulk and at the surface the quasi-particle spectra are evaluated using the dynamical mean field theory. It is shown that as a result of the reduced coordination number of surface atoms correlation effects are stronger at the surface than in the bulk, in agreement with experiment.