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

Giada Franceschi; Renè Heller; Michael Schmid; Ulrike Diebold; Michele Riva

doi:10.1039/d3na00847a

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

Nanoscale Adv. 2023 Nov 2;5(24):7009-7017. doi: 10.1039/d3na00847a. eCollection 2023 Dec 5.

Authors

Giada Franceschi¹, Renè Heller², Michael Schmid¹, Ulrike Diebold¹, Michele Riva¹

Affiliations

¹ Institute of Applied Physics, TU Wien Wiedner Hauptstraβe 8-10/E134 1040 Vienna Austria franceschi@iap.tuwien.ac.at.
² Institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-Rossendorf e.V., Bautzner Landstraße 400 01328 Dresden Germany.

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-xSr_xMnO_3-δ, x ≈ 0.2) on SrTiO₃(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 causes the structure of the surface to evolve accordingly. 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.