PAIRING OF HYDROGEN-ATOMS ON THE SI(100)-2 X-1 SURFACE - THE ROLE OF INTERACTIONS AMONG DIMERS

Local-density-functional calculations of the pairing of H atoms on the (100)-2 x 1 surface of Si are presented. We find that significant interactions between neighboring dimers along a row are present, favoring configurations where H-unpaired dimers are in the same row and have the H atoms all on the same side. We discuss how these effects can contribute to the effective H-pairing energies determined experimentally.