Hybrid density functional theory study of substitutional Gd in β-Ga₂O₃

Substitutional gadolinium alloying in -Ga₂O₃ is studied using hybrid density functional theory. Calculations of structural properties revealed a monotonic increase in lattice parameters, volume and interplanar spacing with increasing gadolinium content. Cohesive energy and formation energy calculations showed monotonically decreasing energy for increased gadolinium concentrations, implying stability even for large concentration gadolinium alloying. The frequency dependent dielectric response spectra reveal spatial anisotropy and a red shift for all optical properties for gadolinium content up to 37.5%, which, coupled with the electronic structure results show how gadolinium alloying may be used to tune Ga₂O₃ without significantly modifying the band edge contributions.