Screened moments in a Kondo insulator

TL;DR

This paper reports the discovery of a bulk moment-screening effect in SmB6, a Kondo insulator, explaining its metallic-like properties through impurity interactions, and broadening the understanding of strongly correlated insulators.

Contribution

It introduces a novel bulk screening effect in SmB6, linking impurity interactions to its unusual thermodynamic and transport properties, expanding the understanding of Kondo insulators.

Findings

Observation of bulk moment-screening in SmB6

Explanation of metallic phenomena via impurity effects

Implications for strongly-correlated insulators

Abstract

Long known to have thermodynamic properties at odds with its insulating electrical transport, SmB6 has been the subject of great debate as it is unclear whether its unusual properties are related to the bulk or novel metallic surface states. We have observed a bulk moment-screening effect in nominally pure and Gd-doped SmB6 via heat capacity, magnetization, and resistivity measurements, and show this new Kondo-impurity like effect provides an unexpected but intuitive explanation for metal-like phenomena stemming from the strongly interacting host system. This affords a coherent understanding for decades of mysteries in strongly-correlated insulators, reveals the expanded utility of techniques previously only utilized for metals, and presents the novel effect of even highly-dilute impurities in strongly correlated insulators.