Electronic structure of the Mott insulator LaVO3 in a quantum well geometry

TL;DR

This study uses x-ray photoemission spectroscopy to explore the electronic structure of LaVO3 in a quantum well geometry, revealing layer-specific valence states and interface properties in oxide ultrathin films.

Contribution

It demonstrates the ability to probe interface electronic structures in ultrathin oxide films using surface-sensitive spectroscopy techniques.

Findings

V 2p spectra show mixed V3+ and V4+ states

V4+ is localized at the topmost layer

Bulk-like spectra observed above 2 unit cells

Abstract

We used x-ray photoemission spectroscopy to investigate the electronic structure of the Mott insulator LaVO3 embedded in LaAlO3. By limiting the upper layer of LaAlO3 to 3 unit cells, the underlying LaVO3 could be probed. The V 2p core-level spectra had both V3+ and V4+ components, and above 2 unit cell thick LaVO3, the structures exhibited spectra similar to bulk samples. The atomically flat surfaces enabled study of the emission angle dependence, which indicates the V4+ is localized to the topmost layer. These results demonstrate the potential for probing interface electronic structure in oxide ultrathin films by surface spectroscopy.