JETP Letters

, Volume 96, Issue 6, pp 397-404

First online:

Nature of the quantum critical point as disclosed by extraordinary behavior of magnetotransport and the lorentz number in the heavy-fermion metal YbRh2Si2

  • V. R. ShaginyanAffiliated withPetersburg Nuclear Physics InstituteClark Atlanta University Email author 
  • , A. Z. MsezaneAffiliated withClark Atlanta University
  • , K. G. PopovAffiliated withKomi Science Center, Ural Division, Russian Academy of Sciences
  • , J. W. ClarkAffiliated withMcDonnell Center for the Space Sciences and Department of Physics, Washington University
  • , M. V. ZverevAffiliated withNational Research Centre Kurchatov InstituteMoscow Institute of Physics and Technology
  • , V. A. KhodelAffiliated withMcDonnell Center for the Space Sciences and Department of Physics, Washington UniversityNational Research Centre Kurchatov Institute

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Physicists are engaged in vigorous debate on the nature of the quantum critical points (QCP) governing the low-temperature properties of heavy-fermion metals. Recent experimental observations of the much-studied compound YbRh2Si2 in the regime of vanishing temperature incisively probe the nature of its magnetic-field-tuned QCP. The jumps revealed both in the residual resistivity ρ0 and the Hall resistivity R H, along with violation of the Wiedemann-Franz law, provide vital clues to the origin of such non-Fermi-liquid behavior. The empirical facts point unambiguously to association of the observed QCP with a fermion-condensation phase transition. Based on this insight, the resistivities ρ0 and R H are predicted to show jumps at the crossing of the QCP produced by application of a magnetic field, with attendant violation of the Wiedemann-Franz law. It is further demonstrated that experimentally identifiable multiple energy scales are related to the scaling behavior of the effective mass of the quasiparticles responsible for the low-temperature properties of such heavy-fermion metals.