Rare Earth Monopnictides and Monochalcogenides from First Principles: Towards an Electronic Phase Diagram of Strongly Correlated Materials

TL;DR

This study uses first-principles calculations to map the electronic phase diagram of 140 rare earth monopnictides and monochalcogenides, revealing diverse electronic behaviors and valency transitions with high accuracy.

Contribution

It provides the first comprehensive ab-initio phase diagram for these compounds, capturing complex electron localization and valency phenomena.

Findings

Predicted metallic, semiconducting, and heavy fermion regions.

Identified valency transitions influenced by ligand chemistry.

Achieved lattice parameter accuracy within 1.5% of experimental data.

Abstract

We present results of an ab-initio study of the electronic structure of 140 rare earth compounds. Specifically we predict an electronic phase diagram of the entire range of rare earth monopnictides and monochalcogenides, composed of metallic, semiconducting and heavy fermion-like regions, and exhibiting valency transitions brought about by a complex interplay between ligand chemistry and lanthanide contraction. The calculations exploit the combined effect of a first-principles methodology, which can adequately describe the dual character of electrons, itinerant vs. localized, and high throughput computing made possible by the increasing available computational power. Our findings, including the predicted "intermediate valent" compounds SmO and TmSe, are in overall excellent agreement with the available experimental data. The accuracy of the approach, proven e.g. through the lattice parameters calculated to within 1.5% of the experimental values, and its ability to describe localization phenomena in solids, makes it a competitive atomistic simulation approach in the search for and design of new materials with specific physical properties and possible technological applications.