Surface Strain Effects on the Adsorption of Au Adatoms on MgO(001) Surfaces with Surface O Vacancies

Abstract

By employing ab-initio total-energy and electronic-structure calculations based on the density-functional theory, we studied the effects of surface strain es on the adsorption properties of a Au adatom on defective MgO(001) surfaces with surface oxygen vacancies (Fs centers). The formation energy of the Fs center on MgO(001) varied very slightly in the region of es from −6% to −4% and monotonically decreased with the increase in es, from −4% to +6%. As es increased, the adsorption energy ( $$E_{ads}^{{F_S}}$$ ) of Au on the es center of strained MgO(001) monotonically decreased and, in particular, showed a much larger decrease in $$E_{ads}^{{F_S}}$$ for a tensile surface strain of es > +4%. The surface strain dependence on the physical properties, such as the charge states, the spatial charge rearrangement, for Au on the Fs center of strained MgO(001) surfaces was also analyzed. These results provide important physical information on the effects of surface strain on the adsorption of Au on MgO(001) surfaces with Fs centers.