Linear strain and stress potential parameters for the three fundamental band to band transitions in β-Ga2O3

We report the strain and stress relationships for the three lowest energy direct band to band transitions at the Brillouin zone center in monoclinic β-Ga2O3. These relationships augment four linear perturbation parameters for situations, which maintain the monoclinic symmetry, which are reported here as numerical values obtained from density functional theory calculations. With knowledge of these perturbation parameters, the shift of each of the three lowest band to band transition energies can be predicted from the knowledge of the specific state of strain or stress, thus providing a useful tool for modeling performance of power electronic devices and rational strain engineering in heteroepitaxy