Bulk and surface-sensitive high-resolution photoemission study of Mott-Hubbard systems SrVO${}_3$ and CaVO${}_3$

Abstract

We study the electronic structure of Mott-Hubbard systems SrVO${}_3$ and CaVO${}_3$ with bulk and surface-sensitive high-resolution photoemission spectroscopy (PES), using a VUV laser, synchrotron radiation and a discharge lamp ($h\nu$ = 7 - 21 eV). A systematic suppression of the density of states (DOS) within $\sim$ 0.2 eV of the Fermi level ($E_F$) is found on decreasing photon energy i.e. on increasing bulk sensitivity. The coherent band in SrVO${}_3$ and CaVO${}_3$ is shown to consist of surface and bulk derived features, separated in energy. The stronger distortion on surface of CaVO${}_3$ compared to SrVO${}_3$ leads to higher surface metallicity in the coherent DOS at $E_F$, consistent with recent theory.

4 pages 5 figures (including 2 auxiliary figures); A complete analysis of the spectra based on the surface and bulk analysis shows in auxiliary figures Fig. A1 and A2