Nature of the Quantum Critical Point As Disclosed by Extraordinary Behavior of Magnetotransport and the Lorentz Number in the Heavy-Fermion Metal YbRh2Si2

作者：Shaginyan V R^*; Msezane A Z; Popov K G; Clark J W; Zverev M V; Khodel V A

来源：JETP Letters, 2012, 96(6): 397-404.

DOI：10.1134/S0021364012180105

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 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 heavy-fermion metals. DOI: 10.1134/S0021364012180105

• 出版日期2012-11