Full charge incorporation in ab initio simulations of two-dimensional semiconductor-based devices

Quantum transport simulations based on the non-equilibrium Green's function formalism require accurate integration of the charges in the system. We demonstrate our implementation of a full charge integration scheme, which automatically incorporates electronic screening effects and is predicted to incorporate interface charges more correctly than the simpler excess charge approach. We first show that under certain conditions the two approaches are equivalent, e.g., for single doping type purely semiconducting devices. We then demonstrate that for devices containing metals, the two approaches may sometimes demonstrate significantly different behavior.