Molecular dynamics simulation of radiation damage production in cubic silicon carbide

Silicon carbide (SiC) is a candidate material for nuclear fusion reactor blankets; hence the importance of investigating its response to irradiation. Molecular dynamics (MD) simulations are a powerful tool to study radiation-damage production from the microscopic standpoint. Results of displacement-cascade MD simulations, conducted using the Tersoff potential to describe the interatomic forces, are presented herein. The number of point-defects produced in the material by silicon- (Si) and carbon- (C) primary knock-on atoms (PKAs) of increasing energy (between 0.25 and, respectively, 8 and 4 keV) is studied systematically. By comparison with standard theoretical models, threshold-displacement-energy (TDE) values of practical usefulness for SiC are derived. The effect of irradiation temperature is also allowed for. Qualitatively, the C sublattice turns out to be more heavily damaged than the Si sublattice. The effect of the irradiation temperature becomes visible only above ≈2000 K.