Computational study of the dielectric properties of [La,Sc]2O3 solid solutions

TL;DR

This study uses first-principles calculations to explore how substituting Sc into La2O3 affects dielectric properties, predicting enhancement in crystalline phases but not in amorphous structures due to local environmental effects.

Contribution

It provides the first computational analysis of dielectric permittivity changes in [La,Sc]2O3 solid solutions across different structural phases.

Findings

Dielectric permittivity increases at small Sc concentrations in cubic and hexagonal phases.

Amorphous La2O3 shows little change in permittivity with Sc substitution.

Local environment effects in amorphous structures counteract rattling ion effects.

Abstract

First-principles calculations were used to compute the dielectric permittivities of hypothetical [La,Sc]2O3 solid solutions in the cubic (bixbyite) and hexagonal La2O3 phases. Dielectric enhancement is predicted at small Sc concentrations due to the rattling ion effect. Similar calculations for a model amorphous La2O3 structure show little change in permittivity when a small amount of Sc is substituted for La. In this case, the local environment around the Sc changes in a way that compensates for the rattling ion effect.