Surface vs. bulk Coulomb correlations in photoemission spectra of perovskites

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.