Charge transfer, surface charging, and overlayer-induced faceting

Local density functional calculations are used to analyze the change of surface energy of metallic surfaces upon surface charging. We then studied the systems involving overlayers of fcc metals on Mo(111) and Mo(211). It has been observed experimentally that some fcc overlayers can drive Mo(111) and W(111) surfaces to facet to the {211} orientation, and there is a strong correlation between the electronegativity of the overlayer and the faceting transformation. Only strongly electronegative fcc elements can cause the faceting, and we apply our analysis to see whether surface charging is main driving mechanism in view of such an empirical correlation. Our results show that surface charging is not the dominant force driving the growth-induced faceting phenomena.