Investigating Interface Phenomena Across Length Scales: From DFT to Empirical Molecular Dynamics

Understanding the interface between solid materials is a complex problem that, while often investigated experimentally, is complicated theoretically by the size limitation in performing molecular dynamics (MD) simulations from first-principles, and thus empirical potentials are sought. However, generating reliable potentials to describe interfaces where the complex bonding and charge environments are considered is challenging. In this work, we derive a charge-optimized many-body (COMB) potential to describe the bonding, charge, and electrostatics of the interface between ZnSe and Al₂O₃, aiming to investigate the behavior at high temperatures. Our COMB potential is parameterized using density functional theory (DFT) calculations of the electronic, structural, and elastic properties of materials that may potentially be part of the interface system. Using our COMB potential in MD simulations, we can explain the effects of different ZnSe - Al₂O₃ interface geometries, the roughness of the interface (i.e., crystallographic steps or vacancies), and the effects of diffused interstitial species.