Polytypism and surface structure of SiC

Within the framework of density functional theory (DFT) in the local density approximation (LDA) using ultrasoft VanderbiIt pseudopotentials in a plane wave basis we investigate the atomic and electronic structure of 3C SiC(111) and nH SiC(0001) surfaces (1 x 1 and root 3 x root 3 reconstructions) and of 3C SiC(00 (1) over bar) surfaces (2 x 2. reconstructions). Since (111)/(0001) is the natural growth direction, the 3C SiC(111)/nH SiC(0001) surfaces are of special interest. Atomic geometries of various reconstructions, their relative stability and their electronic structure (surface band structure) are discussed. The theoretical results are compared with available experiments, (C) 1997 Elsevier Science S.A.