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

TL;DR

This study uses high-resolution photoemission spectroscopy to analyze the electronic structure of SrVO$_3$ and CaVO$_3$, revealing surface and bulk features and how surface distortion affects metallicity.

Contribution

It provides a detailed surface and bulk electronic structure comparison of SrVO$_3$ and CaVO$_3$ using advanced photoemission techniques, highlighting surface effects.

Findings

Suppression of DOS near $E_F$ with increased bulk sensitivity.

Surface and bulk features are separated in energy in the coherent band.

Surface distortion enhances surface metallicity in 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.