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arXiv · 1207.2449

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. Shaginyan·A. Z. Msezane·K. G. Popov·J. W. Clark·M. V. Zverev·V. A. Khodel
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Abstract

Physicists are engaged in vigorous debate on the nature of the quantum critical points (QCP) governing the low-temperature properties of heavy-fermion (HF) 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 rho_0 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 rho_0 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 HF metals.

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V. R. Shaginyan, A. Z. Msezane, K. G. Popov, J. W. Clark, M. V. Zverev, V. A. Khodel. 2012-07-10. Nature of the quantum critical point as disclosed by extraordinary behavior of magnetotransport and the Lorentz number in the heavy-fermion metal YbRh2Si2. https://doi.org/10.1134/s0021364012180105

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