Twirling and spontaneous symmetry breaking of domain wall networks in lattice-reconstructed heterostructures of 2D materials

Lattice relaxation in twistronic bilayers with close lattice parameters and almost perfect crystallographic alignment of the layers results in the transformation of moiré pattern into a sequence of preferential stacking domains and domain wall networks. Here, we show that reconstructed moiré superlattices of the perfectly aligned heterobilayers of same-chalcogen transition metal dichalcogenides have broken-symmetry structures featuring twisted nodes (’twirls’) of domain wall networks. The analysis of twist-angle-dependence of strain characteristics for
the broken-symmetry structures shows that the formation of twirl reduces the amount of hydrostatic strain around the nodes, potentially, reducing their influence on the band edge energies of electrons and holes.