LOCALIZATION PROPERTIES OF THE NONBONDING PI-STATES AT THE FERMI LEVEL IN AMORPHOUS-CARBON

The -electronic structure of graphitelike clusters of amorphous carbon (a-C) containing nonbonding states (=EF) is studied in the tight-binding approximation. The localization characteristics of the eigenstates, especially around the Fermi level, are analyzed. These orbitals were found to be more localized than in aromatic molecules. The nonbonding states are concentrated on surface atoms of the clusters, which implies that the additional hydrogen atoms removing the midgap states link probably to the circumference of the graphitelike regions of a-C. © 1990 The American Physical Society.