Electron-beam charge injection for contactless small-angle alignment in graphene/hBN heterostructures

The ability to dynamically control the relative orientation of layers in two-dimensional (2D) van der Waals (vdW) heterostructures represents a critical step toward the realization of reconfigurable nanoscale devices. Existing actuation methods often rely on mechanical contact, complex architectures, or extreme operating conditions, which limit their applicability and scalability. In this work, we present a proof-of-concept demonstration of contactless electrostatic actuation based on electron-beam-induced charge injection. By locally charging an insulating hexagonal boron nitride (hBN) flake on an electrically grounded graphene layer, we create an interfacial electric field that generates in-plane electrostatic torque and induces angular displacement. The resulting small-angle alignment of the graphene/hBN heterostructure is confirmed through in-situ scanning electron microscopy (SEM) and twist-dependent Raman spectroscopy.