Moiré Valleytronics: Realizing Dense Arrays of Topological Helical Channels*

In hexagonal 2D crystals, the valley degree of freedom is characterized by non-trivial Berry curvatures. Velley-dependent topological helical channels are novel conducting states without back scattering, which can benefit to low power consumption in practical applications. We propose a general, robust and experimentally-feasible platform, the moiré valleytronics, to realize high-density arrays of 1D topological helical channels in real materials at room temperature. We demonstrate the idea using a long-period 1D moiré pattern of graphene on hBN by first-principles calculation. Through calculating the Berry curvature and topological charge of the electronic structure associated with various local graphene/hBN stackings in the moiré pattern, it is revealed that the helical channel arrays originate intrinsically from the periodic modulation of the local topological orders by the moiré pattern.