Evidence of a kondo destroying quantum critical point in YbRh2Si2

Frank Steglich, Heike Pfau, Stefan Lausberg, Sandra Hamann, Peijie Sun, Ulrike Stockert, Manuel Brando, Sven Friedemann, Cornelius Krellner, Christoph Geibel, Steffen Wirth, Stefan Kirchner, Elihu Abrahams, Qimiao Si

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Abstract

The heavy-fermion metal YbRh2Si2 is a weak antiferromagnet below TN = 0.07 K. Application of a low magnetic field Bc = 0.06 T (⊥c) is sufficient to continuously suppress the antiferromagnetic (AF) order. Below T ≈ 10 K, the Sommerfeld coefficient of the electronic specific heat £(T ) exhibits a logarithmic divergence. At T < 0.3 K, γ( T ) ∼ T (ε: 0.3- 0.4), while the electrical resistivity γ(T ) = ρ0 + aT (ρ0: residual resistivity). Upon extrapolating finite-T data of transport and thermodynamic quantities to T = 0, one observes (i) a vanishing of the "Fermi surface crossover" scale T∗- (B), (ii) an abrupt jump of the initial Hall coefficient RH(B) and (iii) a violation of the Wiedemann Franz law at B = Bc, the field-induced quantum critical point (QCP). These observations are interpreted as evidence of a critical destruction of the heavy quasiparticles, i.e., propagating Kondo singlets, at the QCP of this material.

Original languageEnglish (US)
Article number061001
JournalJournal of the Physical Society of Japan
Volume83
Issue number6
DOIs
StatePublished - Jun 15 2014

All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

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