RECONSTRUCTED PSEUDOMORPHIC CO FILMS ON THE CR(110) SURFACE

Ultrathin epitaxial Co films on Cr(110) are examined by high-resolutio n low-energy electron diffraction. Pseudomorphic Co growth occurs over the entire coverage range investigated, i.e., up to 30 ML. A periodic lattice distortion is observed to exist in two equivalent (3X1) recon struction domains showing uniaxial superperiodicity along either one o f the two in-plane close-packed row directions. The lattice reconstruc tion is extended over several atomic layers normal to the surface. It is concluded that the overlayer reconstructs due to the constraint to adopt an inherently unstable structure forced by pseudomorphism. [S016 3-1829(98)50108-7].