Kinetic asymmetry in the growth of two-dimensional Mn oxide nanostripes

Abstract

Nanostripes with very high (>20) aspect ratios of a two-dimensional manganese oxide phase are grown on the Ag(100) surface using a physical vapor deposition method and thoroughly characterized via low-energy electron diffraction and scanning tunneling microscopy. Despite the square pattern of the substrate, symmetry breaking is produced by the structural anisotropy of the kinetically stabilized, metastable Mn surface oxide phase. As rationalized by a first-principles analysis, the resulting asymmetry in edge diffusion and attachment energies and the difference in adsorption energetics between Mn and Ag adatoms leads to the kinetic formation of such strikingly anisotropic structural domains: they feature nanoscale width (\ensuremath{\approx}5--20 nm), mesoscopic length (up to \ensuremath{\approx}1 \ensuremath{\mu}), very low defect density, and grow along the high-symmetry directions of the Ag(100) substrate.