DIAMOND(111) AND DIAMOND(100) SURFACE - AB-INITIO STUDY OF THE ATOMIC-STRUCTURE AND ELECTRONIC-STRUCTURE

Within the framework of density-functional theory in local-density app roximation (DFT-LDA) we perform first-principles calculations for the atomic and electronic str ucture of diamond surfaces. The electron-ion interaction is described by a soft non-local carbon pseudpotential. F or the C(100) surface we find a 2 x 1 reconstruction of symmetric dime rs to be energetically favourable. For the C(111) surface we compare t he surface energies of various reconstructions. In case of the single- bond (one-dimensional) 2 x 1 reconstructed cleavage face we find the p i-bonded chain model to be lowest in energy, whereas at the triple-bon d (three-dimensional) face a (root 3 x root 3)R30 degrees adatom like model is similar in energy to the 2 x 1 single-chain model. For the eq uilibrium geometries we determine band structures and ionization energ ies.