Molecular dynamics simulation in single crystal 3C-SiC under nanoindentation: Formation of prismatic loops

We investigate the formation mechanism of prismatic loops in a 3C-SiC single crystal subjected to nanoindentations on its (111) and (110) surface with a fictitious spherical indenter using molecular dynamics simulation. On the (111) surface, the simulated plastic deformation proceeds with the nucleation and expansion of shear loops, which react with each other to form prismatic loops eventually. Further analysis reveal that the prismatic loops form from one single shear loop or two independent shear loops. For the former, the two screw components of one shear loop undergo cross-slip and form a prismatic loop by the lasso-like mechanism. For the latter, two independent shear loops intersect and evolve into a prismatic loop by an extended lasso-like mechanism, which is also manifested in the nanoindentation on 3C-SiC (110). These results could provide a further understanding for plastic deformation in 3C-SiC nanocrystal materials.