Charge optimized many-body (COMB) potential for Al₂O₃ materials, interfaces, and nanostructures

This work presents the development and applications of a new empirical, variable charge potential for Al₂O₃ systems within the charge optimized many-body (COMB) potential framework. The potential can describe the fundamental physical properties of Al₂O₃, including cohesive energy, elastic constants, defect formation energies, surface energies and phonon properties of α-Al₂O₃ comparable to that obtained from experiments and first-principles calculations. The potential is further employed in classical molecular dynamics (MD) simulations to validate and predict the properties of the Al (1 1 1)–Al₂O₃ (0 0 0 1) interface, tensile properties of Al nanowires, Al₂O₃ nanowires, Al₂O₃-covered Al nanowires, and defective Al₂O₃ nanowires. The results demonstrate that the potential is well-suited to model heterogeneous material systems involving Al and Al₂O₃. Most importantly, the parameters can be seamlessly coupled with COMB3 parameters for other materials to enable MD simulations of a wide range of heterogeneous material systems. (paper)