Length-scales of interfacial coupling between metal-insulator phases in oxides

TL;DR

This study investigates the length scale of interfacial coupling in metal-insulator transitions within oxides, revealing that it is governed by a balance of domain wall energy and bulk energetics, which surpasses structural coupling effects.

Contribution

The paper introduces a novel approach to control and understand the length scale of phase transitions in oxides through engineered superlattices and combined experimental-theoretical analysis.

Findings

Length scale exceeds structural motif coupling

Controlled by domain wall and bulk energetics balance

Introduces new paradigm for interface engineering

Abstract

Controlling phase transitions in transition metal oxides remains a central feature of both technological and fundamental scientific relevance. A well-known example is the metal-insulator transition which has been shown to be highly controllable while a less well understood aspect of this phenomenon is the length scale over which the phases can be established. To gain further insight into this issue, we have atomically engineered an artificially phase separated system through fabricating epitaxial superlattices consisting of SmNiO$_{3}$ and NdNiO$_{3}$, two materials undergoing a metal-to-insulator transition at different temperatures. By combining advanced experimental techniques and theoretical modeling, we demonstrate that the length scale of the metal-insulator transition is controlled by the balance of the energy cost of the domain wall between a metal and insulator and the bulk energetics. Notably, we show that the length scale of this effect exceeds that of the physical coupling of structural motifs, introducing a new paradigm for interface-engineering properties that are not available in bulk