Direct visualization of coexisting channels of interaction in CeSb

TL;DR

This paper uses advanced spectroscopy to directly visualize two distinct interaction channels in CeSb, revealing how different modes coexist by acting on separate carriers and spatially separating their effects.

Contribution

It provides the first direct visualization of coexisting interaction channels in CeSb, showing their separation in momentum space and advancing understanding of correlated electron systems.

Findings

Two distinct interaction modes are simultaneously active in CeSb.

Different modes act on separate types of carriers.

Interaction modes are separated in momentum space, enabling coexistence.

Abstract

Our understanding of correlated electron systems is vexed by the complexity of their interactions. Heavy fermion compounds are archetypal examples of this physics, leading to exotic properties that weave together magnetism, superconductivity and strange metal behavior. The Kondo semimetal CeSb is an unusual example where different channels of interaction not only coexist, but their physical signatures are coincident, leading to decades of debate about the microscopic picture describing the interactions between the $f$ moments and the itinerant electron sea. Using angle-resolved photoemission spectroscopy, we resonantly enhance the response of the Ce$f$-electrons across the magnetic transitions of CeSb and find there are two distinct modes of interaction that are simultaneously active, but on different kinds of carriers. This study is a direct visualization of how correlated systems can reconcile the coexistence of different modes on interaction - by separating their action in momentum space, they allow their coexistence in real space.