Quantum and Classical Molecular Dynamics Studies of the Threshold Displacement Energy in Si Bulk and Nanowires

Abstract

AbstractUsing quantum mechanical and classical molecular dynamics computer simulations, we study the full three-dimensional threshold displacement energy surface in Si. We show that the SIESTA density-functional theory method gives a minimum threshold energy of 13 eV that agrees very well with experiments, and predicts an average threshold displacement energy of 36 eV. Using the quantum mechanical result as a baseline, we discuss the reliability of the classical potentials with respect to their description of the threshold energies. We also examine the threshold energies for sputtering in a nanowire, and find that this threshold depends surprisingly strongly on which layer the atom is in.