Evolution of the surface atomic structure of multielement oxide films: curse or blessing?

Abstract

Atomically resolved scanning tunneling microscopy (STM) and x-ray photoelectron spectroscopy (XPS) are used to gain atomic-scale insights into the heteroepitaxy of lanthanum-strontium manganite (LSMO, La${}_{1-x}$Sr${}_x$MnO${}_{3-\delta }$, $x$ $\approx$ 0.2) on SrTiO${}_3$(110). LSMO is a perovskite oxide characterized by several composition-dependent surface reconstructions. The flexibility of the surface allows it to incorporate nonstoichiometries during growth, which result in composition-dependent surface atomic structures. This happens up to a critical point, where phase separation occurs, clusters rich in the excess cations form at the surface, and films show a rough morphology. To limit the nonstoichiometry introduced by non-optimal growth conditions, it proves useful to monitor the changes in surface atomic structures as a function of the PLD parameters and tune the latter accordingly.

8 pages, 5 figures

References in corpus (3)

• Critical thickness and orbital ordering in ultrathin La0.7Sr0.3MnO3 films
• Surface Reconstructions in Molecular Beam Epitaxy of SrTiO3
• Reconstruction changes drive surface diffusion and determine the flatness of oxide surfaces