Finite-bias first-principles calculation of 2D devices and its multi-scale extensions

Abstract

Zigzag graphene edge (ZGE) is known as containing the ferromagnetically-aligned spin-polarized states. In this dissertation, based on first-principles calculations, we demonstrate that the spin-polarized states of ZGEs are well preserved if the ZGEs are passivated by silicon atoms. We next study how the spin-polarized currents flowing across the vacuum gap separating two graphene electrodes terminated by zigzag edges. In the second part, in view of the development of first-principles-based semiconductor device simulation software, we report the realization of a Python steering method for legacy Fortran codes, and its application to theparallel Laplacian calculations. We close this thesis by discussing the follow-up development directions of this Python-Fortran steering method to enable first-principles-based technology computer-aided design (TCAD) simulations of next-generation semiconductor devices such as 2D spin devices.