Electron correlation effects at semiconductor interfaces: a comparison of the Si 111/-3=3 and the SnrGe 111/-3=3 reconstructions

Electron correlation effects for the Si 111.-3=3 and SnrGe 111.-3=3 reconstructions are analysed introducing 2-dimensional 2D. Hamiltonians whose parameters are deduced from DFT calculations. We find that these two surfaces present striking similarities, with two dangling bonds and one electron per unit cell defining the surface states properties around the Fermi level. Upon introduction of electron correlation effects, the SnrGe 111.-3=3 remains metallic, while the Si 111.-3=3 is found to be semiconducting, mainly due to a kind of charge transfer metal–insulator transition associated with the faulted-unfaulted asymmetry of the surface. q2000 Elsevier Science B.V. All rights reserved.