Spin-selective Kondo insulator: Cooperation of ferromagnetism and Kondo effect

TL;DR

This paper introduces the concept of spin-selective Kondo insulators, explaining how ferromagnetism and Kondo effects cooperate to produce a phase where majority spins are metallic and minority spins are insulating, revealing new insights into magnetic Kondo systems.

Contribution

It proposes the spin-selective Kondo insulator as a new fundamental mechanism for ferromagnetic phases in Kondo lattice models with antiferromagnetic coupling.

Findings

Majority-spin electrons are metallic, minority-spin electrons are insulating.

Kondo gap arises from cooperation of ferromagnetism and partial Kondo screening.

Predicts relations between magnetization, spin polarization, and electron filling.

Abstract

We propose the notion of spin-selective Kondo insulator, which provides a fundamental mechanism to describe the ferromagnetic phase of the Kondo lattice model with antiferromagnetic coupling. This unveils a remarkable feature of the ferromagnetic metallic phase: the majority-spin conduction electrons show metallic- while the minority-spin electrons show insulating-behavior. The resulting Kondo gap in the minority spin sector, which is due to the cooperation of ferromagnetism and partial Kondo screening, evidences a dynamically-induced commensurability for a combination of minority-spin electrons and parts of localized spins. Furthermore, this mechanism predicts a nontrivial relation between the macroscopic quantities such as electron magnetization, spin polarization and electron filling.