Multiple stacking fault formation via the evolution of related dislocations by molecular dynamics simulations

Quality improvement of 3C-SiC material is at present a rapidly growing and intensively exploited field of research. One of the main issues to be solved stems in the high density of extended defects such as dislocations and stacking faults (SFs). The lack of a proper understanding of defects behavior has limited the possibility to overcome these issues. We show that large-scale molecular-dynamics (MD) simulations can strongly help in rationalizing such a complex behavior. After having implemented a script allowing for the insertion of partial dislocation loops within the Large-scale Atomic/Molecular Massively Parallel Simulator LAMMPS [1], we carried out an extensive set of MD simulations based on the Vashista potential [2]. The latter is particularly well suited to investigate defects such as SFs because it allows one to differentiate the energy of SiC hexagonal versus cubic phases. From trajectory analysis we were able to directly observe the evolution of the initial loop, establishing a direct link between its dynamic behavior and the formation of multi-plane SFs in 3C-SiC, therefore shedding light on the formation of such commonly observed defects. In particular we found that an already developed loop locally lowers the energy barriers for the nucleation of another adjacent loop. [1] S. Plimpton, J Comp Phys, 117, 1-19 (1995) [2] P. Vashishta et al., J App Phys, 101, 10 (2007)