GEOMETRY AND ELECTRONIC BAND-STRUCTURE OF AN ORDERED MONOLAYER DEPOSITION OF BI ON III-V(110) SEMICONDUCTOR SURFACES

We present calculational studies of the electronic and geometric structure of an ordered monolayer deposition of Bi on III-V(110) surfaces. The technique which we have applied to these systems relies on the complete self-consistent solution of the Kohn-Sham equations for both the electronic and ionic degrees of freedom. An ab initio pseudopotential method, within the local-density approximation, is used in a supercell approach. From a given initial set of atomic positions, a conjugate-gradient technique is used to achieve the equilibrium geometry by moving along the Born-Oppenheimer subspace. The calculated relaxed geometries of the clean and Bi-covered (110) surface of GaAs, InP, and InAs compare well with available low-energy electron-diffraction and x-ray standing-wave studies, and the electronic band structures agree with angle-resolved photoemission results. The orbital nature of states that might participate in Schottky-barrier formation at Bi-covered surfaces is also discussed. © 1995 The American Physical Society.