Epitaxial strain modulated electronic properties of interface controlled nickelate superlattice

TL;DR

This study demonstrates how epitaxial strain influences the electronic and magnetic properties of EuNiO3/LaNiO3 superlattices, inducing and controlling metal-insulator transitions through strain without chemical doping.

Contribution

It reveals strain-induced control of electronic phases in nickelate superlattices, highlighting the role of epitaxial strain in modulating interface-driven properties.

Findings

Tensile strain induces metal-insulator transition below room temperature.

Large tensile strain separates magnetic and electronic transitions.

Small compressive strain suppresses the transitions entirely.

Abstract

Perovskite nickelate heterostructure consisting of single unit cell of EuNiO$_3$ and LaNiO$_3$ have been grown on a set of single crystalline substrates by pulsed laser interval deposition to investigate the effect of epitaxial strain on electronic and magnetic properties at the extreme interface limit. Despite the variation of substrate in-plane lattice constants and lattice symmetry, the structural response to heterostructuring is primarily controlled by the presence of EuNiO$_3$ layer. In sharp contrast to bulk LaNiO$_3$ or EuNiO$_3$, the superlattices grown under tensile strains exhibit metal to insulator transition (MIT) below room temperature. The onset of magnetic and electronic transitions associated with the MIT can be further separated by application of large tensile strain. Furthermore, these transitions can be entirely suppressed by very small compressive strain. X-ray resonant absorption spectroscopy measurements reveal that such strain-controlled MIT is directly linked to strain induced self-doping effect without any chemical doping.