Local epitaxy of Ag on Bi2Sr2CaCu2O8+x(001).

Abstract

Thin films of Ag have been deposited onto cleaved ${\mathrm{Bi}}_{2}$${\mathrm{Sr}}_{2}$${\mathrm{CaCu}}_{2}$${\mathrm{O}}_{8+\mathit{x}}$(001) surfaces at room temperature. Ag 3d x-ray photoelectron diffraction experiments show very poor local order at coverages of up to 7 \AA{}. For higher Ag coverages, a distinct diffraction pattern is forming, indicative of local epitaxy in the form of two domains of Ag(110) patches with one diagonal of the rectangular surface unit cell aligned along the substrate a axis. Comparison with previously published scanning-tunneling-microscopy results [Y. S. Luo et al., Phys. Rev. B 46, 1114 (1992)] leads us to the conclusion that Ag epitaxy is promoted by local disruption of the substrate upon initial Ag deposition.