Zeeman-driven Lifshitz transition: A scenario for the Fermi-surface reconstruction in YbRh2Si2

TL;DR

This paper proposes that the Fermi-surface reconstruction in YbRh2Si2 is better explained by a Zeeman-driven Lifshitz transition of heavy-fermion bands rather than Kondo breakdown, aligning well with experimental observations.

Contribution

It introduces a quasiparticle model showing that a Lifshitz transition can account for key experimental signatures in YbRh2Si2, challenging the Kondo breakdown interpretation.

Findings

Smeared jump in Hall constant consistent with experiments

Maxima in susceptibility and specific heat lines match data

Emergence of non-Fermi liquid regime near transition

Abstract

The heavy-fermion metal YbRh2Si2 displays a field-driven quantum phase transition where signatures of a Fermi-surface reconstruction have been identified, often interpreted as breakdown of the Kondo effect. We argue that instead many properties of the material can be consistently described assuming a Zeeman-driven Lifshitz transition of narrow heavy-fermion bands. Using a suitable quasiparticle model, we find a smeared jump in the Hall constant and lines of maxima in susceptibility and specific heat, very similar to experimental data. An intermediate non-Fermi liquid regime emerges due to the small effective Fermi energy near the transition. Further experiments to discriminate the different scenarios are proposed.