Geometry and electronic structure of InP(001)(2 x 4) reconstructions

We investigate the atomic and electronic structure of the InP(001) surface by means of first-principles pseudopotential calculations within density-functional theory. We are able to rule out (4 x 2) reconstruction models as well as trimer configurations proposed recently as possible equilibrium structures. We predict (2 x 4) reconstructions characterized by asymmetric In-P or symmetric P dimers for an In-rich and a balanced 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 structures are characterized by filled and empty surface bands close to the bulk valence and conduction band edges, respectively. Details of the geometry and electronic properties for the various possible surface reconstructions are given and compared with the experimental data available. (C) 1998 Elsevier Science B.V. All rights reserved.