Atomic Scale Relaxation at the van der Waals Interface in Twisted Bilayer Graphene

Adjusting stacking angle in two-dimensional van der Waals (vdW) atomic layers allows engineering physical properties of the heterostructures. Rotational lattice mismatch creates additional quasiperiodic structures described by moiré patterns, modifying the electronic band structures. More interestingly, the quasiperiodic moiré structures can be reconstructed into commensurate domain structures as a result of interplay between vdW interaction energy and elastic energy at the interface. The commensurate domains are topologically nontrivial in the presence of vertical displacement field, providing a network of one-dimensional transport modes along their boundaries. In this talk, we present transmission electron microscopy results to discuss the microstructures of twisted bilayer graphene. Electrical transport behavior with controlled vertical displacement field and carrier density was investigated to understand the effect of commensurate domains and their boundaries on the charge transport behavior.