Surface versus bulk Coulomb correlations in photoemission spectra of SrVO3 and CaVO3

Recent photoemission spectra of the perovskite series CaxSr1-xVO3 revealed strong modifications associated with surface contributions. To study the effect of Coulomb correlations in the bulk and at the surface, the quasiparticle 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.