Nitrogen-induced pseudo-(100) reconstruction of the Cu(111) surface identified by STM

The N-induced reconstruction of Cu(111) has been studied using scanning tunnelling microscopy (STM). The results fully support a model, previously proposed on the basis of qualitative interpretation of the LEED pattern, in which the outermost Cu atom layer adopts a distorted pseudo-(100) structure with the adsorbed atomic N forming a c(2 x 2) periodicity on this reconstructed Cu layer. Both the c(2 x 2) and (1 x 1) periodicities of this pseudo-(100) surface were imaged under different tip conditions; these show clearly that there is no 'clock reconstruction' of the pseudo-(100) layer as reported for C on Ni(111). A periodic corrugation observed in the height of the reconstructed phase has been modelled by a simple hard-sphere simulation of the effects of the variations in local registry between the pseudo-(100) layer and the underlying (111) substrate based on a true (25 x 7 root 3)rect. coincidence surface mesh. (C) 1999 Elsevier Science B.V. All rights reserved.