High magnetic fields thermodynamics of heavy fermion metal YbRh2Si2

TL;DR

This paper provides a comprehensive theoretical analysis of the thermodynamic behavior of the heavy-fermion compound YbRh2Si2 under high magnetic fields, explaining its quantum criticality, metamagnetic transition, and NFL properties.

Contribution

It introduces a theoretical framework that explains the high-field thermodynamics and quantum critical behavior of YbRh2Si2, aligning well with experimental observations.

Findings

High magnetic fields polarize quasiparticle bands and induce a Landau Fermi liquid state.

Fermion condensation quantum phase transition explains non-Fermi liquid behavior.

Quasiparticles survive at high temperatures and magnetic fields.

Abstract

We perform comprehensive theoretical analysis of high magnetic field behavior of the heavy-fermion (HF) compound YbRh2Si2. At low magnetic fields B, YbRh2Si2 has a quantum critical point related to the suppression of antiferromagnetic ordering at a critical magnetic field. Our calculations of the thermodynamic properties of YbRh2Si2 in wide magnetic field range allow us to straddle a possible metamagnetic transition region and probe the properties of both low-field HF liquid and high-field fully polarized one. Namely, high magnetic fields B\sim B^*\sim 10 T fully polarize corresponding quasiparticle band generating Landau Fermi liquid (LFL) state and suppressing HF (actually NFL) one, while at elevating temperatures both HF state and corresponding NFL properties are restored. Our calculations are in good agreement with experimental facts and show that the fermion condensation quantum phase transition is indeed responsible for the observed NFL behavior and quasiparticles survive both high temperatures and high magnetic fields.