He diffraction and scanning-tunneling-microscopy investigations on the growth of the Cu{110}-(2×1)O added-row structure reveal a novel phenomenon: the long-range spatial self-organization of two-dimensional islands. In a wide coverage range the anisotropic Cu-O islands arrange themselves in a striped periodic supergrating, with the stripes running along the 〈001〉 direction. The spacing of the supergrating depends on oxygen coverage and temperature and varies between 140 and 60 Å.

• Received 3 May 1991

DOI:https://doi.org/10.1103/PhysRevLett.67.855