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.

This work is financially supported by the Natural Science and Engineering Research Council (NSERC) of Canada (H. G.) and the Research Grants Council of Hong Kong (HKU17302617). We thank Compute Canada and the High Performance Computing Center of McGill University for substantial computational support.