Ultrahigh Stability of O-Sublattice in -Ga₂O₃

Recently reported remarkably high radiation tolerance of /-Ga₂O₃ double-polymorphic structure brings this ultrawide bandgap semiconductor to the frontiers of power electronics applications that are able to operate in challenging environments. Understanding the mechanism of radiation tolerance is crucial for further material modification and tailoring of the desired properties. In this study, we employ machine-learning-enhanced atomistic simulations to assess the stability of both the gallium (Ga) and oxygen (O) sublattices under various levels of damage. Our study uncovers the remarkable resilience and stability of the O-sublattice, attributing this property to the strong tendency of recovery of the O defects, especially within the stronger disordered regions. Interestingly, we observe the opposite behavior of the Ga defects that display enhanced stability in the same regions of increased disorder. Moreover, we observe that highly defective -Ga₂O₃ is able to transform into -Ga₂O₃ upon annealing due to preserved lattice organization of the O-sublattice. This result clearly manifests that the ultrahigh stability of the O-sublattice provides the backbone for the exceptional radiation tolerance of the / double-polymorphic structure. These computational insights closely align with experimental observations, opening avenues for further exploration of polymorphism in Ga₂O₃ and potentially in analogous polymorphic families spanning a broad range of diverse materials of complex polymorphic nature.