Unfolding the Electronic Bands of 2D Heterostructures

Abstract

We investigate electronic bands in hexagonal-rectangular 2D heterostructures, where layer interactions, broken symmetries, and reduced dimensionality can yield novel properties. Density Functional Theory (DFT) is employed to optimize such systems, with supercells constructed via a mismatch minimization approach. A WSe2-bP heterostructure is modeled using tetralayer bP combined with either monolayer or bilayer WSe2, and optimized with the OpenMX code. Band structure analysis reveals highly folded bands, and, by the projection operator method, unfolded bands are obtained. The case of bilayer WSe2 with a decoupling effect due to bP shows hybridization induced minigap openings. The upward shift of the WSe2 valence band maximum suggests symmetry-driven electronic modifications, pointing to potential spontaneous photovoltaic effects in hexagonal-rectangular interfaces.