Structural, Dymanical, and Electronic Properties of Amorphous Silicon: Anab initioMolecular-Dynamics Study

An amorphous silicon structure is obtained with a computer simulation based on a new moleculardynamics technique in which the interatomic potential is derived from a parameter-free quantum-mechanical method. Our results for the atomic structure, the phonon spectrum, and the electronic properties are in excellent agreement with experiment. In addition we study details of the microscopic dynamics which are not directly accessibly to experiment. We find in particular that structural defects are associated with weak bonds. These may give rise to low-frequency vibrational modes.