Electronic Structure of Lanthanide Scandates

TL;DR

This study combines experimental spectroscopy and advanced density functional theory calculations to analyze the electronic structure of lanthanide scandates, revealing a closer proximity of minority Ln4f states to the valence band maximum than previously believed.

Contribution

It introduces a hybrid computational approach that accurately models the electronic structure of lanthanide scandates, highlighting the significant role of minority Ln4f electrons.

Findings

Minority Ln4f states are closer to the valence band maximum than previously thought.

The hybrid DFT method aligns well with experimental spectra.

Minority Ln4f electrons may influence properties more than earlier assumed.

Abstract

X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy and density functional theory calculations were used to study the electronic structure of three lanthanide scandates: GdScO3, TbScO3, and DyScO3. X-ray photoelectron spectra simulated from first principles calculations using a combination of on-site hybrid and GGA+U methods were found to be in good agreement with experimental x-ray photoelectron spectra. The hybrid method was used to model the ground state electronic structure and the GGA+U method accounted for the shift of valence state energies due to photoelectron emission via a Slater-Janak transition state approach. From these results, the lanthanide scandate valence bands were determined to be composed of Ln4f, O2p, and Sc3d states, in agreement with previous work. However, contrary to previous work the minority Ln4f states were found to be located closer to, and in some cases at, the valence band maximum. This suggests that minority Ln4f electrons may play a larger role in lanthanide scandate properties than previously thought.