Epitaxial growth of (111)-oriented LaAlO$_3$/LaNiO$_3$ ultra-thin superlattices

TL;DR

This paper reports the successful epitaxial growth of high-quality LaNiO$_3$/LaAlO$_3$ (111) superlattices on polar LaAlO$_3$ substrates, enabling exploration of topological properties in complex oxide interfaces.

Contribution

It demonstrates a method to synthesize high-quality (111)-oriented superlattices of complex oxides overcoming interface polarity issues.

Findings

High structural and chemical quality confirmed by X-ray techniques.

Successful epitaxial stabilization of LaNiO$_3$/LaAlO$_3$ superlattices on polar (111) surfaces.

Potential for fabricating topology-controlled oxide superlattices.

Abstract

The epitaxial stabilization of a single layer or superlattice structures composed of complex oxide materials on polar (111) surfaces is severely burdened by reconstructions at the interface, that commonly arise to neutralize the polarity. We report on the synthesis of high quality LaNiO$_3$/mLaAlO$_3$ pseudo cubic (111) superlattices on polar (111)-oriented LaAlO$_3$, the proposed complex oxide candidate for a topological insulating behavior. Comprehensive X-Ray diffraction measurements, RHEED, and element specific resonant X-ray absorption spectroscopy affirm their high structural and chemical quality. The study offers an opportunity to fabricate interesting interface and topology controlled (111) oriented superlattices based on ortho-nickelates.