  Twistronic heterostructures have recently emerged as a new class of quantum
electronic materials with properties determined by the twist angle between the
adjacent two-dimensional materials. Here we study moir\'e superlattice
minibands in graphene (G) encapsulated in hexagonal boron nitride (hBN) with an
almost perfect alignment with both the top and bottom hBN crystals. We show
that, for such an orientation of the unit cells of the hBN layers that locally
breaks inversion symmetry of the graphene lattice, the hBN/G/hBN structure
features a Kagom\'e network of topologically protected chiral states with
energies near the miniband edge, propagating along the lines separating the
areas with different miniband Chern numbers.

Mesoscale and Nanoscale Physics