A scanning tunneling microscope (STM) showed the formation of nanometer size c(2×2) domains of adsorbed oxygen on the Cu(100) surface when oxygen coverage is low, though large well-ordered c(2×2) domains were not observed. The STM image of the phase boundaries of these nanometer size c(2×2)-O domains showed complex zigzag bright lines surrounding the c(2×2) domains, and the low-energy electron diffraction pattern of this surface gave a ‘‘four-spot’’ pattern, which can be explained by a local c(2×2) domain model. © 1996 The American Physical Society.

• Received 14 March 1996

DOI:https://doi.org/10.1103/PhysRevB.54.2167