REACTION PATHWAY FOR SB-DIMER ROTATION IN CONVERSION OF SB-4 PRECURSORS ON SI(OO1)

We report first-principles total-energy calculations that provide deta iled reaction pathways for Sb-dimer rotation in evolving processes of Sb-4 precursors on the Si(001) surface. We find that the total energy for the Sb dimer perpendicular to the subsurface Si dimers is lower th an the parallel dimer by 0.45 eV. We also find a plausible reaction pa thway for the Sb-dimer rotation during which only a single dangling bo nd is created. The calculated activation energy for the rotation is 1. 0 eV, indicative that the dimer rotation is rate-determining in the ev olving process of Sb-4 precursors.