Sequential localization of a complex electron fluid

TL;DR

This paper investigates electron localization in a complex quantum material, revealing two distinct transitions driven by separate degrees of freedom, and introduces the concept of sequential destruction of spin-orbital entanglement.

Contribution

It demonstrates that electron localization can occur via sequential transitions driven by different degrees of freedom in a heavy fermion system, advancing understanding of correlated electron behavior.

Findings

Two distinct localization transitions driven by separate degrees of freedom.

Sequential destruction of SU(4) spin-orbital Kondo entanglement.

Simplified low-energy behavior explains complex localization phenomena.

Abstract

Complex and correlated quantum systems with promise for new functionality often involve entwined electronic degrees of freedom. In such materials, highly unusual properties emerge and could be the result of electron localization. Here, a cubic heavy fermion metal governed by spins and orbitals is chosen as a model system for this physics. Its properties are found to originate from surprisingly simple low-energy behavior, with two distinct localization transitions driven by a single degree of freedom at a time. This result is unexpected, but we are able to understand it by advancing the notion of sequential destruction of an SU(4) spin-orbital-coupled Kondo entanglement. Our results implicate electron localization as a unified framework for strongly correlated materials and suggest ways to exploit multiple degrees of freedom for quantum engineering.