Adsorption of glycine on Cu(001) and related step faceting and bunching

Adsorption of glycine on the Cu(001) surface has been studied with scanning tunneling microscopy. In addition to confirming the Cu(001)c(2×4)-glycine to be the major superstructure on the surface, it has been found that on the surface all steps are faceted to 〈310〉 directions and that the faceted steps may bunch together to form Cu{3 1 17}1×1-glycine facets. On the basis of our STM images and the local structure of glycine adsorbed on Cu(110) reported recently, models have been proposed for the Cu(001)c(2×4)- and Cu(3 1 17)1×1-glycine superstructures for further investigation. The models explain quite naturally the motivations behind the step faceting and bunching prosesses.