Optimizing Lennard-Jones Potential for Simulating Rocksalt CdO Crystal and Ga + Implantation with Molecular Dynamics

Cadmium oxide (CdO) is a tunable semiconducting material, which is capable of altering its optical and semiconducting properties based on the doping-induced defects in the material. Thin films of CdO can exhibit critical metamaterial properties, including epsilon-near-zero (ENZ) with appropriate doping and thickness. Traditional ion implantation schemes are challenging to apply for shallow implantation, so we turn to local doping at lower voltage using Ga+ focused ion beam (FIB) due to its operation at relatively low energy (30 kV) compared to the familiar broad ion sources. However, ion channeling and the damage it induces at the interface between the thin films and the substrate are critical aspects of such implantation endeavors. Here, molecular dynamics (MD) simulations can be advantageous because they help predict ion-channeling effects along crystal geometries. In this paper, we demonstrate the successful implementation of Lennard-Jones (LJ) potentials to simulate a CdO crystal using MD. The demonstrated approach provides an easy yet robust and unique way to simulate ion trajectories when bombarded on the crystalline CdO. Moreover, the presented workflow can be applied to a wide range of metal-oxide materials due to the simple form of LJ potentials.