Equilibrium Structures and Finite Temperature Properties of Silicon Microclusters fromab initioMolecular-Dynamics Calculations

We show that new aspects of the physics of microclusters can be investigated accurately with ab initio molecular dynamics. We present results on a number of properties of ${\mathrm{Si}}_N$ aggregates ($N$ up to 10) at both zero and finite temperatures. The results of dynamical simulated annealing for the ground state point to a complex growth sequence. Simulations at finite temperatures show the existence of two regimes, solidlike and liquidlike, with substantially different electronic and structural properties.