We report on the faceting of Cu(115) surfaces upon oxygen adsorption,
as studied by scanning tunnelling microscopy. For temperatures around
500 K, during or after oxygen adsorption, pronounced faceting into (10
4), (014) and (113) facets is observed. Details of the facet structure
s were analyzed. The (113) facet exhibits an additional reconstruction
which can be described as a c(7 x 12) superstructure. The development
of Cu-O-Cu atomic chains is suggested to be the driving force for the
oxygen-induced surface reconstruction.