Dislocation Networks in Marginally Twisted Bilayer MoS2

초록

In marginally twisted van der Waals homo- and heterostructures, spontaneous atomic reconstruction forms commensurate stacking domains separated by domain boundaries, which can be regarded as dislocations. Here, we employ dark field transmission electron microscopy combined with diffraction-contrast analysis to identify the Burgers vectors of domain boundaries within reconstructed domain boundary networks. Owing to the atomically thin nature of two-dimensional (2D) materials, diffraction contrast can be interpreted within a kinematical approximation, enabling simple and accessible analysis of dislocation character. In marginally twisted bilayer MoS2 with antiparallel stacking, large hexagonal MX ' domains are enclosed by networks of screw-type perfect dislocations. As the twist angle increases, these hexagonal domains evolve into triangular MX ' domains, accompanied by a reorganization of the domain boundary from hexagonal networks of perfect dislocations to triangular networks of partial dislocations. Our work establishes an accessible framework for resolving dislocation networks and their twist-angle-driven evolution in reconstructed twisted 2D materials.