Structure and chemical bonding in amorphous diamond

The atomic structures of relaxed amorphous carbon models with diamond density are investigated, and the related scattering, electronic, and vibrational properties are analysed. Purely tetrahedrally coordinated models were generated using a bond switch Monte Carlo algorithm similar to the Wooten-Winer-Weaire method for amorphous silicon. These defect-free models are compared with models produced by density-functional-based tight-binding molecular dynamics as well as by molecular dynamics using the classical Tersoff potential. The stability and properties of ''amorphous diamond'' are discussed, and the consequences for network strain and gap states of frequently appearing undercoordinated atoms are deduced.