Crystal structure and properties of barium thorate BaThO$_3$ from first principles

TL;DR

This study uses first-principles calculations to analyze the phonon spectrum, structural phases, and physical properties of cubic BaThO$_3$, revealing its ground-state structure and potential phase transitions.

Contribution

It provides the first detailed theoretical analysis of BaThO$_3$'s structure, properties, and phase transition possibilities using density functional theory.

Findings

Ground-state structure is Pbnm

Calculated dielectric constants and elastic moduli

Identified potential structural phase transitions

Abstract

The phonon spectrum of cubic BaThO$_3$ with the perovskite structure is calculated from first principles within the density functional theory. The analysis of unstable modes in the phonon spectrum enables to determine the symmetry of all possible distorted phases, calculate their energies, and show that the ground-state structure of barium thorate is $Pbnm$. For this structure, the static and optical dielectric constants, elastic moduli, heat capacity, Raman spectra, and the energy band gap in the LDA and $GW$ approximations are calculated. The possibility of the structural phase transitions in BaThO$_3$ is also discussed.