Break up of heavy fermions at an antiferromagnetic instability

Abstract

We present results of high-resolution, low-temperature measurements of the Hall coefficient, thermopower, and specific heat on stoichiometric YbRh2Si2. They support earlier conclusions of an electronic (Kondo-breakdown) quantum critical point concurring with a field induced antiferromagnetic one. We also discuss the detachment of the two instabilities under chemical pressure. Volume compression/expansion (via substituting Rh by Co/Ir) results in a stabilization/weakening of magnetic order. Moderate Ir substitution leads to a non-Fermi-liquid phase, in which the magnetic moments are neither ordered nor screened by the Kondo effect. The so-derived zero-temperature global phase diagram promises future studies to explore the nature of the Kondo breakdown quantum critical point without any interfering magnetism.

minor changes, accepted for publication in JPSJ

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Cited by in corpus (6)

• Hall effect in heavy-fermion metals
• Strongly correlated Fermi systems as a new state of matter
• Comment on "Zeeman-Driven Lifshitz Transition: A Model for the Experimentally Observed Fermi-Surface Reconstruction in YbRh2Si2"
• Quantum criticality in the spin-isotropic pseudogap Bose-Fermi Kondo model: entropy, scaling, and the g-theorem
• Scaling behavior of the thermopower of the archetypical heavy-fermion metal $\mathrm{YbR}{\mathrm{h}}_2\mathrm{S}{\mathrm{i}}_2$
• Critical quasiparticle theory: Scaling, thermodynamic and transport properties