Formation of ion irradiation induced small-scale defects on graphite surfaces

We use molecular dynamics simulations and ab initio calculations to study the structures and formation probabilities of isolated surface defects produced by ion irradiation of (1000) graphite. We improve the conventionally used Tersoff potential [J. Tersoff, Phys. Rev. Lett. 61, 2879 (1988)] to realistically describe interlayer forces in graphite and high-energy processes in carbon. We identify three defect structures which correspond to experimentally observed hillocks on graphite surfaces, and examine their formation at different implantation energies.