Layered Kondo lattice model for quantum critical beta-YbAlB4

TL;DR

This paper proposes a layered Kondo lattice model for beta-YbAlB4, explaining its quantum critical behavior and predicting changes in electronic anisotropy under pressure.

Contribution

The paper introduces a novel layered Kondo lattice model combining realistic material analysis and crystal field theory for beta-YbAlB4.

Findings

Model fits measured magnetic susceptibility.

Predicts electronic anisotropy change under pressure.

Provides insights into quantum criticality in heavy fermion systems.

Abstract

We analyze the magnetic and electronic properties of the quantum critical heavy fermion superconductor beta-YbAlB4, calculating the Fermi surface and the angular dependence of the extremal orbits relevant to the de Haas--van Alphen measurements. Using a combination of the realistic materials modeling and single-ion crystal field analysis, we are led to propose a layered Kondo lattice model for this system, in which two dimensional boron layers are Kondo coupled via interlayer Yb moments in a $J_{z}=\pm 5/2$ state. This model fits the measured single ion magnetic susceptibility and predicts a substantial change in the electronic anisotropy as the system is pressure-tuned through the quantum critical point.