Antiferromagnetism mediated by heavy electrons: singlet shielding vs "high-order" RKKY

TL;DR

This paper investigates whether antiferromagnetic order can be mediated by heavy electrons through a high-order RKKY interaction, revealing coexistence with metallicity and implications for heavy fermion materials.

Contribution

It introduces a model showing AF order mediated by heavy electrons via high-order RKKY, a novel mechanism differing from traditional conduction electron mediation.

Findings

AF order can be mediated via heavy electrons.

AF order coexists with metallicity in certain regimes.

Heavy electrons' breakdown destroys AF order.

Abstract

Can the antiferromagnetic (AF) order be induced via the local moments' hybridization with the heavy electrons instead of conduction electrons? We address this intriguingly fundamental question via a prototypical model to describe the interplay between local moments and heavy electrons. We discover that the AF order can be mediated via the heavy electrons through the mechanism of "high-order" Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction. Moreover, the induced AF order can coexist with its metallicity in a finite regime of the phase diagram, which competes with and ultimately destroys the AF order concurrently with the breakdown of heavy electrons. The potential relevance to the heavy fermion compound Ce$_3$(Pt/Pd)In$_{11}$ is discussed.