MOLECULAR DYNAMIC INVESTIGATIONS OF AMORPHOUS-CARBON - PI-BONDING VS ELECTRONIC DEFECT GENERATION

The local electronic bonding properties of amorphous carbon (a-C) structures with varying microscopic mass densities, ranging from 2.0 to 3.5 g cm-3, are analysed. Using a semiempirical density functional approach the model structures were generated by molecular dynamics performing a rapid quenching of 128-atom liquid carbon clusters within periodically arranged cubic supercells. The chemical bonding properties are evaluated within a local valence orbital description giving rise to a strong control of electronic properties and quality in a-C materials by the balance between pi bonding formation and electronic defect generation.