2D Surface Phase Diagram of a Multicomponent Perovskite Oxide: La$_{0.8}$Sr$_{0.2}$MnO$_3$(110)

TL;DR

This study maps the surface phase diagram of La$_{0.8}$Sr$_{0.2}$MnO$_3$(110), revealing how oxygen chemical potential influences surface reconstructions and phase separation, with implications for material surface properties.

Contribution

The paper provides the first detailed 2D phase diagram of LSMO(110) surface structures as a function of oxygen chemical potential and composition.

Findings

Decreasing $rac{}{}O$ induces Mn migration and phase separation.

Surface reconstructions are composition-dependent and structurally diverse.

STM quantifies phase-separated surface structures.

Abstract

The many surface reconstructions of (110)-oriented lanthanum--strontium manganite (La$_{0.8}$Sr$_{0.2}$MnO$_3$, LSMO) were followed as a function of the oxygen chemical potential ($\mu_\text{O}$) and the surface cation composition. Decreasing $\mu_\text{O}$ causes Mn to migrate across the surface, enforcing phase separation into A-site-rich areas and a variety of composition-related, structurally diverse B-site-rich reconstructions. The composition of these phase-separated structures was quantified with scanning tunneling microscopy (STM), and these results were used to build a 2D phase diagram of the LSMO(110) equilibrium surface structures.