Impact of the angular alignment on the crystal field and intrinsic doping of bilayer graphene/BN heterostructures

TL;DR

This study investigates how the angular alignment in bilayer graphene/BN heterostructures influences the crystal field and doping, revealing the critical role of layer orientation beyond moiré effects.

Contribution

The paper introduces a novel device architecture to control displacement field and alignment, providing new insights into the impact of twist angle on internal fields and doping in heterostructures.

Findings

Crystal field and doping reflect the 120° symmetry of the heterostructure.

Alignment significantly affects internal electric fields and doping levels.

Layer orientation plays a crucial role beyond moiré superlattice effects.

Abstract

The ability to tune the energy gap in bilayer graphene makes it the perfect playground for the study of the effects of internal electric fields, such as the crystalline field, which are developed \Reb{when other layered materials are deposited on top of it}. Here, we introduce a novel device architecture allowing a simultaneous control over the applied displacement field and the crystalline alignment between two materials. Our experimental and numerical results confirm that the crystal field and electrostatic doping due to the interface reflect the 120$^{\circ}$ symmetry of the bilayer graphene/BN heterostructure and are highly affected by the commensurate state. These results provide an unique insight into the role of twist angle in the development of internal crystal fields and intrinsic electrostatic doping in heterostructures. Our results highlight the importance of layer alignment, beyond the existence of a moir\'e superlattice, to understand the intrinsic properties of a heterostructure.