Unravelling the electromechanical coupling in a graphene/bulk h-BN heterostructure

The stacking heterostructure of graphene on bulk h-BN produces a moire pattern with topographic corrugation. The corrugation of the moire pattern expectantly induces a considerable curvature and a flexoelectric response, which calls for a detailed study. In this work, we used lateral force microscopy, a scanning technique to locally observe the moire pattern and topographic corrugation. The curvature and flexoelectric potentials are derived from the measured topographic corrugation, revealing a huge curvature of similar to 10(7) m(-1) and a flexoelectric potential of similar to 10 mV in the hexagonal domain wall region (similar to 3-4 nm) of the moire pattern. In addition, the domain walls of the moire pattern also generate a clear electromechanical and frictional response, arising from the corrugation-induced flexoelectric response. In summary, the results of this work provide insights into the understanding of the flexoelectricity in the graphene/bulk h-BN and its associated electromechanical coupling behavior in the moire pattern of a van der Waals stacking heterostructure.

Automated summary

In this study, the stacking heterostructure of graphene on bulk h-BN was observed using lateral force microscopy. The topographic corrugation of the moire pattern was found to induce considerable curvature and flexoelectric response, with a huge curvature of approximately 10(7) m(-1) and a flexoelectric potential of approximately 10 mV. The domain walls of the moire pattern also exhibited electromechanical and frictional response due to the corrugation-induced flexoelectric response.