Showing papers by "Alex Zunger published in 1974"

A molecular calculation of electronic properties of layered crystals. II. Periodic small cluster calculation for graphite and boron nitride

Abstract: Small (18-32 atoms) periodic clusters of two-dimensional hexagonal graphite and boron nitride are shown to represent some high-symmetry points in the Brillouin zone of the infinite crystal Semi-empirical all-valence electron calculations are performed on these clusters and the binding energy, work function, bandwidth, band-to-band transition energy, band gap, charges and equilibrium distances are computed and compared with values obtained by tight binding and truncated crystal calculations Favourable agreement with experimental data is obtained with selfconsistent calculations on these clusters

A molecular calculation of electronic properties of layered crystals. I. Truncated crystal approach for hexagonal boron nitride

Abstract: A truncated crystal approach is applied to the hexagonal boron nitride structure and electronic properties such as work function, different band widths, energy of band-to-band transition and cohesion energy are studied and compared with tight binding, OPW methods and experimental optical and thermochemical data. It is demonstrated that whenever the relation between one-electron energy levels of a finite molecular cluster and energy states at the Brillouin zone of the crystal are established, good results can be obtained. Properties that are not amenable to calculation by simple band theories, like energy of Frenkel pair formation, point defect states and dependence on interatomic distance of various energy states, are computed by the same method and discussed with reference to experiment.