The f-electron challenge: localized and itinerant states in lanthanide oxides united by GW@LDA+U

TL;DR

This paper applies GW@LDA+U many-body perturbation theory to lanthanide oxides, achieving accurate electronic structure predictions and reproducing experimental optical band gaps with weak U dependence.

Contribution

The study demonstrates that GW@LDA+U provides a reliable and U-robust method for modeling lanthanide oxides' electronic properties, improving upon previous approaches.

Findings

G0W0@LDA+U matches experimental spectra for CeO2 and Ce2O3.

G0W0 shows weak U dependence within a physical range.

Reproduces main features of optical band gaps across Ln2O3 series.

Abstract

Many-body perturbation theory in the GW approach is applied to lanthanide oxides, using the local-density approximation plus a Hubbard U correction (LDA+U) as the starting point. Good agreement between the G0W0 density of states and experimental spectra is observed for CeO2 and Ce2O3. Unlike the LDA+U method G0W0 exhibits only a weak dependence on U in a physically meaningful range of U values. For the whole lanthanide sesquioxide (Ln2O3) series G0W0@LDA+U reproduces the main features found for the optical experimental band gaps. The relative positions of the occupied and unoccupied f-states predicted by G0W0 confirm the experimental conjecture derived from phenomenological arguments.