[SY-G6] Repulsive Correction in Tersoff Potential for Irradiated Si
Engineering applications for nuclear fussion/fission facilities usually require a material with exceptional properties. Silicon carbide (SiC) and its composites are prospective materials for such usage due to low degradation of mechanical properties at high temperature as well as high resistance to irradiation. There are ongoing attempts to employ SiC/SiC composites like flow channel inserts (FCI) in dual coolant lead lithium (DCLL) blankets and fuel claddings for the Generation IV nuclear reactors. SiC/SiC composites are yet to be examined further before confirmed to be the best option. As an example, irradiation damages in SiC/SiC composites may cause a serious problem by interacting with various elements in nuclear operations.
Understanding the microstructural evolution under irradiation is critical to validate SiC/SiC composites and the resulting safety under irradiation, and Molecular dynamics (MD) is a viable option for that purpose. Nevertheless the reliability of MD simulations heavily depends on the accuracy of an interatomic potential. The Tersoff potential is a good candidate, but not particularly optimized for high-energy environment, resulting in a few pathological behaviors.
In this talk we propose a correction function that minimizes the problems of the Tersoff potential developed for bulk equilibrium. In particular, the correction function replaces the repulsive part of Tersoff within a threshold interatomic spacing. The function behaves monotonically and is continuous with the original repulsive part up to the third derivative at the threshold, and moreover, complexity does not increase significantly because the correction function introduces only two additional free parameters. By primary knock-on atom (PKA) simulations, the effect of the correction is examined. We evaluate a maximum penetration length and the number of Frenkel pairs and discuss a benefit from the correction.
Understanding the microstructural evolution under irradiation is critical to validate SiC/SiC composites and the resulting safety under irradiation, and Molecular dynamics (MD) is a viable option for that purpose. Nevertheless the reliability of MD simulations heavily depends on the accuracy of an interatomic potential. The Tersoff potential is a good candidate, but not particularly optimized for high-energy environment, resulting in a few pathological behaviors.
In this talk we propose a correction function that minimizes the problems of the Tersoff potential developed for bulk equilibrium. In particular, the correction function replaces the repulsive part of Tersoff within a threshold interatomic spacing. The function behaves monotonically and is continuous with the original repulsive part up to the third derivative at the threshold, and moreover, complexity does not increase significantly because the correction function introduces only two additional free parameters. By primary knock-on atom (PKA) simulations, the effect of the correction is examined. We evaluate a maximum penetration length and the number of Frenkel pairs and discuss a benefit from the correction.