Abbreviated Journal Title
J. Appl. Phys.
MOLECULAR-DYNAMICS SIMULATION; ORDER; SOLIDIFICATION; TRANSITIONS; FILMS; Physics, Applied
We present a detailed analysis of a recently-developed empirical potential to describe silicon under conditions of strong electronic excitation. The parameters of the potential are given as smooth functions of the electronic temperature T(e), with the dependence determined by fitting to finite-temperature density-functional theory calculations. We analyze the thermodynamics of this potential as a function of the electronic temperature T(e) and lattice temperature T(ion). The potential predicts phonon spectra in good agreement with finite-temperature density-functional theory, including the previously predicted lattice instability. We predict that the melting temperature T(m) decreases strongly as a function of T(e). Electronic excitation has a strong effect on the rate of crystallization from the melt. In particular, high T(e) results in very slow kinetics for growing crystal from the melt, due mainly to the fact that diamond becomes much less stable as T(e) increases. Finally, we explore annealing amorphous Si (a-Si) below T(m), and find that we cannot observe annealing of a-Si directly at high T(e). We hypothesize that this is also due to the decreased stability of the diamond structure at high T(e).
Journal of Applied Physics
Shokeen, Lalit and Schelling, Patrick K., "Thermodynamics and kinetics of silicon under conditions of strong electronic excitation" (2011). Faculty Bibliography 2010s. 1915.