FIRST PRINCIPLES CALCULATION OF OXYGEN-ADSORPTION AND RECONSTRUCTION OF CU(110) SURFACE

We have carried out first principles calculations for the adsorption o f oxygen on the Cu(110) surface. The stable adsorption sites of chemis orbed atomic oxygen on the clean unreconstructed surface are investiga ted at 1/6, 1/2, 2/3 and 1 monolayer (ML) coverage. For the low covera ge case, the O atom is found to be most stable in a position close to the fourfold hollow site. At half coverage, the most stable structure is - in agreement with experiment - the (2 x 1) pairing row reconstruc tion. The electronic properties of the (2 x 1) reconstruction are eval uated and discussed in detail. To study the growth of the (2 x 1) adde d row reconstruction an investigation of the diffusion pathways of Cu and O adatoms on the surface is presented. The diffusion barriers for O adatoms are found to be 150 meV in the [1 (1) over bar 0] and 300 me V in the [001] direction. For Cu adatoms, both the ''jump'' mechanism, by which diffusion parallel to the [001] troughs is accomplished, and the ''exchange'' mechanism, which is responsible for the diffusion pa rallel to the [1 (1) over bar 0] direction, are investigated, and the diffusion barriers are evaluated. We find that the exchange mechanism has a slightly higher barrier (350 meV) than the jump mechanism (230 m eV). The process responsible for the growth of Cu-O-Cu chains parallel to the [001] direction is discussed. (C) 1998 Elsevier Science B.V. A ll rights reserved.