Ab initioand photoemission study of correlation effects in SrRuO3thin films

Abstract

We present the experimental and theoretical study of correlation effects in epitaxial SrRuO${}_{3}$ thin films. Experimentally, we have performed resonant ultraviolet photoemission spectroscopy (UPS) and angle-resolved hard x-ray photoemission spectroscopy (HAXPES) measurements. For resonant UPS, the two methods, Fano-profile fitting of constant initial state spectra and the energy distribution curves equidistant difference spectra, were used to extract Ru 4$d$ partial spectral weight (PSW) in the valence band. We find Ru 4$d$ PSW possessing a clearly pronounced coherent peak at the Fermi level together with angle-resolved HAXPES spectra demonstrating no difference in surface and bulk electronic structure. From comparison of experimental data with theoretical calculations done at density functional theory level, we conclude that SrRuO${}_{3}$ is a weakly correlated material and electronic structure of it can be consistently described employing first-principles approaches.