# Hybrid functional study of non-linear elasticity and internal strain in zincblende III-V materials

## TL;DR

This paper uses hybrid functional density functional theory to accurately predict the elastic constants and internal strain components of zincblende III-V semiconductors, many of which lack experimental data, and discusses the importance of higher order elasticity.

## Contribution

It provides the first theoretical predictions of second and third order elastic constants and internal strain tensors for Ga, In, and Al containing III-V compounds using hybrid functional calculations.

## Key findings

- Predicted elastic constants for materials without experimental data.
- Demonstrated the importance of convergence criteria in calculating higher order elastic constants.
- Identified the strain regime where higher order elasticity effects are significant.

## Abstract

We investigate the elastic properties of selected zincblende III-V semiconductors. Using hybrid functional density functional theory we calculate the second and third order elastic constants, and first and second-order internal strain tensor components for Ga, In and Al containing III-V compounds. For many of these parameters, there are no available experimental measurements, and this work is the first to predict their values. The stricter convergence criteria for the calculation of higher order elastic constants are demonstrated, and arguments are made based on this for extracting these constants via the calculated stresses, rather than the energies, in the context of plane-wave-based calculations. The calculated elastic properties are used to determine the strain regime at which higher order elasticity becomes important by comparing the stresses predicted by a lower and a higher order elasticity theory. Finally, the results are compared with available experimental literature data and previous theory.