Winding Berry dipoles on uniaxially strained graphene/insulator moiré superlattices

Nonlinear Hall-like currents can be generated by a time-periodic alternating bias on two-dimensional (2D) materials lacking inversion symmetry. To hint that the moir\'e pattern between graphene and its supporting substrate contributes to the homogeneity of nonlinear currents, the change in the local potential $\mathrm{\ensuremath{\Delta}}V(\mathbf{r})$ around horizontally strained graphene due to a homobilayer of hexagonal boron nitride (hBN) was obtained from ab initio calculations, and corrections to on-site energies and hopping matrix elements on the tight-binding electronic dispersion of graphene's $\ensuremath{\pi}$ electrons were calculated. Relying on a semiclassical approximation, Berry dipoles $\mathbf{D}$ are seen to change orientation and wind throughout the moir\'e heterostructure.