Electrostatic moire potential from twisted hexagonal boron nitride layers

Abstract

Moire superlattices host a rich variety of correlated electronic phases. However, the moire potential is fixed by interlayer coupling, and it is dependent on the nature of carriers and valleys. In contrast, it has been predicted that twisted hexagonal boron nitride (hBN) layers can impose a periodic electrostatic potential capable of engineering the properties of adjacent functional layers. Here, we show that this potential is described by a theory of electric polarization originating from the interfacial charge redistribution, validated by its dependence on supercell sizes and distance from the twisted interfaces. This enables controllability of the potential depth and profile by controlling the twist angles between the two interfaces. Employing this approach, we further demonstrate how the electrostatic potential from a twisted hBN substrate impedes exciton diffusion in semiconductor monolayers, suggesting opportunities for engineering the properties of adjacent functional layers using the surface potential of a twisted hBN substrate. The authors demonstrate that the electrostatic potential originating on the surface of twisted bilayer and multilayer hexagonal boron nitride can be used to generate a moire potential modulation on adjacent semiconductor layers, enabling the possibility of controlling the properties of this adjacent layer.