Effect of temperature on the dynamics of energetic displacement cascades: A molecular dynamics study

Molecular dynamics simulations of 3-keV displacement cascades in Cu at temperatures of 0, 300, 500, and 700 K have been performed using the Gibson II potential. Most atomic displacements occur in the quasimolten core region that develops at t0.5 ps and persists for several ps. The size and lifetime of the molten regions increase with ambient temperature, which results in a fourfold increase in atomic mixing between 0 to 700 K and a decrease in defect production. The instantaneous diffusion coefficients in the cascade melt are in close agreement with those in the equilibrium liquid.