Ab initio DFT simulation of ideal shear deformation of SiC polytypes

摘要

We perform ab initio density functional calculations to investigate the ideal shear deformation of SiC polytypes (3C, 2H, 4H and 6H). The deformation of the cubic and hexagonal polytypes in the small-strain region can be well represented by the elastic property of component Si4C-tetrahedrons. The stacking pattern in the polytypes affects strain localization, which is correlated with the GSF energy profile of each shuffle-set plane and the ideal shear strength. Compressive hydrostatic stress decreases the ideal shear strength but does not much affect the shear elastic coefficient. Tersoff classical interatomic potential can represent the deformation behaviour of SiC crystals in the small-strain region but cannot be applied to largely sheared and compressed situations.