Spin-flip scattering of critical quasiparticles and the phase diagram of YbRh2Si2

Abstract

Several observed transport and thermodynamic properties of the heavy-fermion compound YbRh2Si2 in the quantum critical regime are unusual and suggest that the fermionic quasiparticles are critical, characterized by a scale-dependent diverging effective mass. A theory based on the concept of critical quasiparticles (CQP) scattering off antiferromagnetic spin fluctuations in a strong-coupling regime has been shown to successfully explain the unusual existing data and to predict a number of so far unobserved properties. In this paper, we point out a new feature of a magnetic field-tuned quantum critical point of a heavy-fermion metal: anomalies in the transport and thermodynamic properties caused by the freezing out of spin-flip scattering of critical quasiparticles and the scattering off collective spin excitations. We show that a step-like behavior as a function of magnetic field of e.g. the Hall coefficient and magnetoresistivity results, which accounts quantitatively for the observed behavior of these quantities. That behavior has been described as a crossover line T*(H) in the T - H phase diagram of YbRh2Si2. Whereas some authors have interpreted this observation as signaling the breakdown of Kondo screening and an associated abrupt change of the Fermi surface, our results suggest that the T* line may be quantitatively understood within the picture of robust critical quasiparticles.

9 pages, 4 figures

References in corpus (9)

• Fermi-liquid instabilities at magnetic quantum phase transitions
• Weak magnetism and non-Fermi liquids near heavy-fermion critical points
• Multiple energy scales at a quantum critical point
• Fermi-surface collapse and dynamical scaling near a quantum critical point
• Orbital-selective Mott transitions: Heavy fermions and beyond
• Divergence of the Magnetic Grüneisen Ratio at the Field-Induced Quantum Critical Point in YbRh${}_2$Si${}_2$
• Electron spin resonance in Kondo systems
• Evolution of the Kondo state of YbRh2Si2 probed by high field ESR
• Magnetization study of the energy scales in YbRh${}_2$Si${}_2$ under chemical pressure

Cited by in corpus (9)

• Grüneisen parameter studies on heavy fermion quantum criticality
• Evolution of the Kondo lattice and non-Fermi liquid excitations in a heavy-fermion metal
• Similar temperature scale for valence changes in Kondo lattices with different Kondo temperatures
• Toward a New Microscopic Framework for Kondo Lattice Materials
• Strong coupling theory of heavy fermion criticality II
• Evolution from Ferromagnetism to Antiferromagnetism in Yb(Rh1-xCox)2Si2
• Electro-nuclear transition into a spatially modulated magnetic state in YbRh${}_2$Si${}_2$
• Demystifying the Holographic Mystique
• Tuning low-energy scales in YbRh${}_2$Si${}_2$ by non-isoelectronic substitution and pressure