Mixed O+N layers on a Rh(110) surface: Competition between nitrogen and oxygen reconstructive interactions

Scanning tunneling microscopy and low energy electron diffraction studies of mixed O+N layers on Rh(110) reveal a competition between (n×{}1) N-driven and (1×{}2) O-driven added/missing row reconstructions. At low coverage [001] N-Rh rows prevail, forming islands with a (3×{}1) periodicity. At moderate coverage separate (2×{}1)N and (1×{}2)O islands are formed. At high coverage the growing (1×{}2)O islands displace those of (2×{}1)N. The structural transformations involve a transition from a structure consisting of separate (2×{}1)N and (1×{}2)O islands to a mixed c(2×{}2)N+O layer on a (1×{}2) reconstructed surface.