Formation of stacking-fault tetrahedra in collision cascades

One of the outstanding questions in radiation damage is how stacking-fault tetrahedra (SFTs) can be formed below the vacancy migration temperature. Using molecular dynamics simulations of energetic collision cascades, we now describe how a stacking-fault tetrahedron can be created directly in a collision cascade. We also show that, while the number of SFTs is small at low temperatures, at elevated temperatures the number will increase by rearrangement of complex damage clusters into the SFTs, in good agreement with experiments. (C) 1999 American Institute of Physics. [S0003-6951(99)04918-9].