Temperature effects on dislocation core energies in silicon and germanium

摘要

Temperature effects on the energetics of the 90-degree partial dislocation insilicon and germanium are investigated, using non-equilibrium methods toestimate free energies, coupled with Monte Carlo simulations. Atomicinteractions are described by Tersoff and EDIP interatomic potentials. Ourresults indicate that the vibrational entropy has the effect of increasing thedifference in free energy between the two possible reconstructions of the90-degree partial, namely, the single-period and the double-period geometries.This effect further increases the energetic stability of the double-periodreconstruction at high temperatures. The results also indicate that anharmoniceffects may play an important role in determining the structural properties ofthese defects in the high-temperature regime.