GEOMETRY AND ELECTRONIC-STRUCTURE OF INP(001)(2 X 4) RECONSTRUCTIONS

We investigate the atomic and electronic structure of the InP(001) sur face by means of first-principles pseudopotential calculations within density-functional theory. We are able to rule out (4 x 2) reconstruct ion models as well as trimer configurations proposed recently as possi ble equilibrium structures. We predict (2 x 4) reconstructions charact erized by asymmetric In-P or symmetric P dimers for an In-rich and a b alanced surface stoichiometry, respectively. For a very limited range of preparation conditions we cannot exclude, however, the existence of further stable (2 x 4) reconstructions. All favourable equilibrium st ructures are characterized by filled and empty surface bands close to the bulk valence and conduction band edges, respectively. Details of t he geometry and electronic properties for the various possible surface reconstructions are given and compared with the experimental data ava ilable. (C) 1998 Elsevier Science B.V. All rights reserved.