Large-scale atomistic study of plasticity in amorphous gallium oxide with ab-initio accuracy

Abstract

Abstract Compared to the widely investigated crystalline polymorphs of gallium oxide ( $${\text {Ga}_{2}\text {O}_{3}}$$ ), knowledge about its amorphous state is very limited. With the help of a machine-learning interatomic potential, we conducted large-scale atomistic simulations to investigate the formation and plastic behavior of amorphous $${\text {Ga}_{2}\text {O}_{3}}$$ (a- $${\text {Ga}_{2}\text {O}_{3}}$$ ). Amorphization of gallium oxide melt is successfully observed at ultrahigh cooling rates, including a distinct glass transition. The glass transition temperature is evaluated to range from 1234 to 1348 K at different cooling rates. Structural analysis shows similarities between a- $${\text {Ga}_{2}\text {O}_{3}}$$ and amorphous alumina (a- $${\text {Al}_{2}\text {O}_{3}}$$ ) in many aspects, including pair distribution function, coordination distribution, and bond angle distribution. In the tension simulations, highly plastic behavior at room temperature is observed, highly comparable to a- $${\text {Al}_{2}\text {O}_{3}}$$ . Based on multiple quantitative characterization results, we show that a- $${\text {Ga}_{2}\text {O}_{3}}$$ exhibits a higher nucleation rate of localized plastic strain events compared to a- $$\text {Al}_{2}\text {O}_{3}$$ , which can increase the material’s resistance to shear banding formation during deformation.