Onset of metallic behavior in strained (LaNiO3)n/(SrMnO3)2 superlattices

TL;DR

This study investigates how strain and layer thickness in LaNiO3/SrMnO3 superlattices influence their electronic behavior, revealing a transition from insulating to metallic states as LaNiO3 layers increase.

Contribution

It demonstrates the controlled tuning of electronic phases in superlattices through layer thickness and strain, using advanced growth and characterization techniques.

Findings

Superlattices are highly crystalline with minimal interfacial roughness.

A clear metal-insulator transition occurs as LaNiO3 layer thickness decreases.

Transport data shows a progression from insulating to metallic behavior with increasing LaNiO3 content.

Abstract

(LaNiO3)n/(SrMnO3)2 superlattices were grown using ozone-assisted molecular beam epitaxy. In situ reflection high energy electron diffraction and x-ray scattering has been used to characterize the structural properties of the superlattices, which are strained to the SrTiO3 substrates. The superlattices exhibit excellent crystallinity and interfacial roughness of less than one unit cell. A metal-insulator transition is observed as $n$ is decreased from 4 to 1. Analysis of the transport data suggests an evolution from gapped insulator (n=1) to hopping conductor (n=2) to metal (n=4) with increasing LaNiO3 concentration.