Current-induced valley polarization switching in magnetic moiré materials*

Large anomalous Hall conductivities have been observed in both transition-metal dichalcogenide and graphene-based moiré materials, and in both cases are attributed to spontaneous valley polarization. Because carriers in opposite valleys have opposite Hall conductivities, this type of orbital magnetism will lead to pumping between valleys [1,2] along the edges of current-carrying Hall bars. We will report on a theory of this effect and its influence on collective valley dynamics and the stability of valley-polarization microstructures. We will also comment on the possible observability of related effects in conventional magnetic conductors.

[1] Sekine, Akihiko, and Allan H. MacDonald. "Valley pumping via edge states and the nonlocal valley Hall effect in two-dimensional semiconductors." Physical Review B 102.15 (2020): 155205.

[2] Beconcini, Michael, Fabio Taddei, and Marco Polini. "Nonlocal topological valley transport at large valley Hall angles." Physical Review B 94.12 (2016): 121408.