Lattice reconstruction in twisted bilayer graphene.

Twisted bilayer graphene (TBG) provides a tunable platform to study emergent properties that are absent in single-layer graphene by the van der Waals (vdW) interlayer interaction. The vdW interlayer interaction can also lead to notable lattice reconstruction at the interface, promoting interlayer commensurability while minimizing intralayer lattice distortion. The lattice reconstruction in TBG is a pivotal phenomenon that significantly influences the optical and electronic properties. Currently, the study of lattice reconstruction in TBG attracts much attention in condensed matter physics. In this article, we review the experimental advances in the field of TBG lattice reconstruction. The formation and atomic-scale characterization within reconstructed TBG are overviewed comprehensively. In addition, lattice reconstruction-induced electronic modulations are introduced. Moreover, coexistence and transition between reconstructed and unreconstructed phases within a critical transition regime are described. Furthermore, we discuss the prospects of tunable reconstruction within TBG and other 2D material heterostructures.