Thermal conductivity in the vicinity of the quantum critical endpoint in Sr3Ru2O7

Abstract

Thermal conductivity of Sr3Ru2O7 was measured down to 40 mK and at magnetic fields through the quantum critical endpoint at H_c = 7.85 T. A peak in the electrical resistivity as a function of field was mimicked by the thermal resistivity. In the limit as T -> 0 K we find that the Wiedemann-Franz law is satisfied to within 5% at all fields, implying that there is no breakdown of the electron despite the destruction of the Fermi liquid state at quantum criticality. A significant change in disorder (from ${\rho }_0$(H=0T) = 2.1 $\mu \Omega$ cm to 0.5 $\mu \Omega$ cm) does not influence our conclusions. At finite temperatures, the temperature dependence of the Lorenz number is consistent with ferromagnetic fluctuations causing the non-Fermi liquid behavior as one would expect at a metamagnetic quantum critical endpoint.

4 figures, published in PRL

References in corpus (5)

• Weak magnetism and non-Fermi liquids near heavy-fermion critical points
• Metamagnetism of itinerant electrons in multi-layer ruthenates
• Metamagnetic quantum criticality in Sr3Ru2O7 studied by thermal expansion
• The Origin of Anomalous Low-Temperature Downturns in the Thermal Conductivity of Cuprates
• Charge instabilities at the metamagnetic transition

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• Low-Temperature Thermal Conductivity of CeRh${}_2$As${}_2$
• Theory of the pairbreaking superconductor-metal transition in nanowires
• The Lorenz ratio as a guide to scattering contributions to Planckian transport
• Lorenz ratio of an impure compensated metal in the degenerate Fermi liquid regime
• Dramatic elastic response at the critical end point in UTe${}_2$
• Flattening of Single-Particle Spectra in Strongly Correlated Electron Systems and the Violation of the Wiedemann-Franz Law
• Observation of microscopic domain effects in the metal-insulator transition of thin-film NdNiO${}_3$