Quantum phase structural stability and switching in twist-graphenes

This study examines the electronic structure and potential energy surfaces of migration paths in various types of bilayer graphene. Using periodic boundary conditions, density functional theory (DFT), and the generalized gradient approximation (GGA) exchange–correlation functional, along with the nudged elastic band (NEB) method, to investigate the structural stability and dynamic equilibrium of twisted bilayer graphenes (TBGs) with twist angles of 13.2° and 21.8°. The results suggest that twist angles significantly impact atomic and electronic properties, including moiré patterns, superlattice periods, and interfragment distances, which in turn influence bilayer graphene strongly correlated electronic quantum states. This research elucidates the fundamental mechanisms of superlubricity and mutual migration pathways of graphene fragments in TBGs. The low migration barriers observed could facilitate transitions between different energy-related phases, which are determined by the lattice moiré patterns and the localization character of the electronic states, resulting in superlubricity. External mechanical factors may affect the quantum properties of TBGs, indicating potential applications in quantum computing and quantum sensing.