Displacement energy surface in 3C and 6H SiC

The phase stability of 3C-SiC upon heating and the threshold displacement energy (E-d) surfaces for C and Si primary knock-on atoms (PKAs) in 3C-SiC and 6H-SiC have been investigated using molecular dynamics simulations. A recently optimized Tersoff potential is used in conjunction with an ab initio repulsive potential to represent the interactions between atoms. The simulations provide important insights into phase separation of SiC upon heating, and indicate a strong anisotropy in the E-d surface for both Si and C PKAs. The two polytypes show many similarities in the nature of the E-d surface. The average displacement energy is separately determined by simulating 30 different 500 eV cascades in 3C-SiC. The minimum displacement energies of 21 eV for C and 35 eV for Si are in excellent agreement with interpretation of experimental observations and the simulations of 500 eV cascades. (C) 2000 Elsevier Science B.V. All rights reserved.