Low-temperature theory of inversion and quantum oscillations in Kondo insulators

TL;DR

This paper develops a low-temperature theoretical framework for Kondo insulators, revealing three insulating phases, including an inverted Kondo singlet, and predicts quantum oscillations with distinctive experimental signatures.

Contribution

It introduces a self-consistent low-temperature theory for Kondo insulators that identifies a novel inverted Kondo singlet phase and characterizes its quantum oscillation behavior.

Findings

Identifies three insulating phases: KS, iKS, and AFM.

Discovers dimensional reduction in the density of states at the inversion transition.

Predicts Lifshitz-Kosevich-like quantum oscillations in the iKS and AFM phases.

Abstract

The half-filled Kondo lattice model is studied at low temperatures on simple cubic lattice using the self-consistent theory developed in Phys. Rev. B 96, 075115 (2017). It is found to have three distinct insulating phases in the temperature-hopping plane, namely, the strong coupling Kondo singlet (KS) phase, the inverted Kondo singlet (iKS) phase distinguished from the KS by inversion, and the antiferromagnetic (AFM) phase. The quasiparticle density of states across the inversion transition is noted to exhibit dimensional reduction, which can differentiate between the KS and iKS insulators in experiments. Magnetic quantum oscillations obtained in the iKS and AFM phases are found to show Lifshitz-Kosevich like behaviour with temperature as well as inverse hopping.