Anomalous Reduction of the Lorenz Ratio at the Quantum Critical Point in YbAgGe

TitleAnomalous Reduction of the Lorenz Ratio at the Quantum Critical Point in YbAgGe
Publication TypeJournal Article
Year of Publication2013
AuthorsDong JK, Tokiwa Y, Bud'ko SL, Canfield PC, Gegenwart P
Journal TitlePhysical Review Letters
Volume110
Pages176402
Date Published04
Type of ArticleArticle
ISBN Number0031-9007
Accession NumberWOS:000317915200019
Keywordsfermi-liquid behavior, heavy fermions, metals, phase-transitions, superconductivity
Abstract

We report measurements of the electrical and thermal transport on the hexagonal heavy-fermion metal YbAgGe for temperatures T >= 40 mK and in magnetic fields H parallel to ab up to 14 T. This distorted kagome-lattice system displays a series of magnetic states and a quantum critical point at H-c = 4.5 T. The Lorenz ratio L(T)/L-0 displays a marked reduction only close to H-c. A T-linear contribution below 120 mK, present at all different fields, allows us to extrapolate the Lorenz ratio towards T = 0. At the critical field this yields L/L-0 = 0.92 +/- 0.03, suggesting a violation of the Wiedemann-Franz law due to strong inelastic scattering. DOI: 10.1103/PhysRevLett.110.176402

URL<Go to ISI>://WOS:000317915200019
DOI10.1103/PhysRevLett.110.176402