DFT study of the formation of the Sb-Ag(1 1 1) (√3×√3) – R30° surface alloy

Abstract

According to performed DFT calculations, the (√3×√3) – R30° structure, in which Sb atoms occupy hcp sites on Ag(111), is more energetically favorable than the related substitutional SbAg2 surface alloy. The difference in energies is significant, 0.66 eV per unit cell, and can be attributed to a larger size of Sb atoms compared to Ag. The obtained results of modeling the substitutional process explain the formation of adsorbed Sb layer on the Ag(111) surface by means of Sb deposition instead of the formation of the substitutional surface alloy. In turn, Ag deposition onto the alloy surface will cause a floating up (segregation to the surface) of Sb atoms thus restoring the alloy surface, which may serve as a surfactant in the process of the growth of Ag crystal.