First-principles study of magnetism and electric field effects in 2D systems

Abstract

This review article provides a bird's-eye view of what first-principles based methods can contribute to next-generation device design and simulation. After a brief overview of methods and capabilities in the area, we focus on published work by our group since 2015 and current work on CrI 3 . We introduce both single-and dual-gate models in the framework of density functional theory and the constrained random phase approximation in estimating the Hubbard U for 2D systems vs. their 3D counterparts. A wide range of systems, including graphene-based heterogeneous systems, transition metal dichalcogenides, and topological insulators, and a rich array of physical phenomena, including the macroscopic origin of polarization, field effects on magnetic order, interface state resonance induced peak in transmission coefficients, spin filtration, etc., are covered. For CrI 3 we present our new results on bilayer systems such as the interplay between stacking and magnetic order, pressure dependence, and electric field induced magnetic phase transitions. We find that a bare bilayer CrI 3 , graphene | bilayer CrI 3 | graphene, h-BN | bilayer CrI 3 | h-BN, and h-BN | bilayer CrI 3 | graphene all have a different response at high field, while small field the difference is small except for graphene | bilayer CrI 3 | graphene. We conclude with discussion of some ongoing work and work planned in the near future, with the inclusion of further method development and applications.