MOLECULARLY INDUCED STEP FACETING ON CU(110) SURFACES

Scanning tunneling microscopy (STM) has been used to study structures formed by adsorbed formate and benzoate species on Cu(110) surfaces. P artially oxygen-precovered and clean surfaces were exposed to formic a nd benzoic acids, respectively. STM images show that both adsorbed for mate and benzoate result in a tendency for bunched steps to align alon g [1(1) over bar2$] directions and to become equidistant effectively c reating small facet planes on the surface. In the case of benzoate, th ese planes can be described as (11 13 1) and (11 13 (1) over bar) plan es. In the case of formate, ordered arrays of facet planes can form on step edges giving the steps a ''sawtooth'' appearance. Under some con ditions adsorbed formate also appears to stabilize finger-like islands and pits.