Structure and Dynamics of the Electronic Heterointerfaces in MoS₂ by First-Principles Simulations

The transformation of 2H-MoS₂ from semiconducting 2H to metallic 1T phases is critical for its electrochemical and device applications, where the formation and dynamics of electronic heterostructures play a key role. Using first-principles calculations, we explore detailed atomic structures and migration processes of such interfaces. While armchair interfacial bonding is severely weakened by the distortion in 1T phase, stable structures form for either Mo- or S-orientated zigzag interfaces with low contact resistance. Different zigzag interfaces have distinct local bonding, which renders interface migration behaviors strongly anisotropic. For Mo-oriented interfaces, both a low formation energy and the migration barrier of the kinks make them prone to fast migration. In contrast, the S-oriented interfaces are more immobile due to the high formation energies of kinks and thus dominate the physical properties of the whole heterostructures. Our findings not only explain various experimental observations but also provide insights into phase transition behaviors in 2D MoS₂.