The truncation of a semiconducting infinite-crystal creates dangling bonds. Hence, complex reconstructions and relaxations occur which redistribute the surface atoms in order to minimize the number of dangling bonds. However, the reconstructions are limited by the ability of the atoms to rehybridize, alter bond lengths, and bend bond angles. Boron, on the other hand, is a small atom. The structure we have determined agrees well with that determined by other surface structural analyses.
Magnesium presents an altogether different case.
Mg-Si bonds per Mg atom. These similarities can be justified by assuming that charge is exchanged between adsorbate and silicon atoms, but the metal atoms are not ordered in the surface unit-cell. This complex phenomenon requires further study. Gold does not readily form a silicide, is not a dopant, and forms complex interfaces when ohmic contacts are created. With all of the above information, our LEED intensity analysis confirmed a structure which is missing the top layer of Si, is trimer-based, has mirror symmetry, and contains very little substrate relaxation.