THEORETICAL-STUDY OF CL ADSORPTION ON THE GAAS(110) SURFACE

The positions and energies of four candidate adsorption sites for Cl on GaAs(110) have been investigated using the ab initio pseudopotential plane-wave method. We obtain general agreement with recent experimental studies on the distribution and pattern formation of Cl adatoms. An analysis of adatom height based on valence charge density agrees quantitatively with reported scanning tunneling microscopy values. For the four adatom sites considered, the relaxation of the first GaAs surface layer was similar to or less than the relaxation of the bare surface. In the case of the lowest energy site, the relaxation is nearly healed due to a change in character of the surface bonding. This is in contrast to conclusions based on core photoemission results and simple charge-transfer arguments. © 1994 The American Physical Society.