Structure of twisted transition metal dichalcogenides

We present density functional theory (DFT) calculations of the reconstruction in MoSe₂/WSe₂ hetero-bilayers twisted a small angle away from 180-degree stacking. The bilayer reconstructs to increase the area of the domains with the lowest energy stacking. The overall twist is concentrated in the domain walls and vertices, where the energetic cost of twisting away from 180 degrees is reduced. We consider the local stacking, order parameter, and strain in the relaxed twisted bilayer.