Molecular-dynamics simulation of threshold displacement energies in BaTiO3

Abstract

Molecular-dynamics simulations were used to calculate threshold displacement energies for each atom type in BaTiO3 perovskite. A primary knock-on atom with an energy range between 10 and 300eV in principal crystallographic directions at 300K was introduced. A statistical approach has been applied calculating displacement probability curves along main crystallographic directions. For each sublattice, the simulation was repeated from different initial conditions to estimate the uncertainty in the threshold displacement energy calculated values. The threshold displacement energies vary considerably with crystallographic direction and sublattice. The weighted average threshold displacement energies are 40eV for oxygen, 64eV for barium and 97eV for titanium atoms. These values are comparable to ab initio calculated and experimentally derived values in perovskites. These results are proposed as threshold displacement energies, ideal for simulation programs that use atomic displacement calculation algorithms.