Bilayer sliding mechanism for the zinc-blende rocksalt transition in SiC

We have theoretically investigated the mechanism of the pressure-induced reconstructive zinc-blende to rocksalt phase transition in SiC. We obtained 925 possible transition pathways (TPs) using a group-theoretical analysis method. This extensive survey of possible TPs is a significant feature which distinguishes this study from previous studies. Of these 925 TPs, we identified eight which have the lowest enthalpy barriers, based on first-principles electronic structure calculations. These eight TPs share a common underlying mechanism: bilayer sliding of (111) planes such that local bonding evolves from tetrahedral to octahedral without breaking any bonds. This mechanism may be applicable to other related transitions involving similar bonding changes.