The Lorenz ratio as a guide to scattering contributions to Planckian transport

Abstract

In many physical situations in which many-body assemblies exist at temperature $T$, a characteristic quantum-mechanical time scale of approximately $\hslash /k_{B}T$ can be identified in both theory and experiment, leading to speculation that it may be the shortest meaningful time in such circumstances. When this behaviour is investigated by probing the scattering rate of strongly interacting electrons in metals, it is clear that in some cases only electron-electron scattering can be its cause, while in others it arises from high-temperature scattering of electrons from quantised lattice vibrations, i.e. phonons. In metallic oxides, which are among the most studied materials, analysis of electrical transport does not satisfactorily identify the relevant scattering mechanism at 'high' temperatures near room temperature. We employ a contactless optical method to measure thermal diffusivity in two Ru-based layered perovskites, Sr${}_3$Ru${}_2$O${}_7$ and Sr${}_2$RuO${}_4$, and use the measurements to extract the dimensionless Lorenz ratio. By comparing our results to the literature data on both conventional and unconventional metals we show how the analysis of high-temperature thermal transport can both give important insight into dominant scattering mechanisms, and be offered as a stringent test of theories attempting to explain anomalous scattering.

27 pages, 8 figures

References in corpus (17)

• Planckian Dissipation in Metals
• Universal theory of strange metals from spatially random interactions
• Superconductivity in an extreme strange metal
• Thermalization and Possible Signatures of Quantum Chaos in Complex Crystalline Materials
• Thermal conductivity in the vicinity of the quantum critical endpoint in Sr3Ru2O7
• A lower bound to the thermal diffusivity of insulators
• Combining Electron-Phonon and Dynamical Mean-Field Theory Calculations of Correlated Materials: Transport in the Correlated Metal Sr${}_2$RuO${}_4$
• A stability bound on the $T$-linear resistivity of conventional metals
• The Wiedemann-Franz law in doped Mott insulators without quasiparticles
• Deviation from the Wiedemann-Franz law induced by nonmagnetic impurities in overdoped La_{2-x}Sr_{x}CuO_{4}
• Breakdown of the Wiedemann-Franz law at the Lifshitz point of strained Sr${}_2$RuO${}_4$
• Thermal conductivity and heat diffusion in the two-dimensional Hubbard model
• A Criterion for Strange Metallicity in the Lorenz Ratio
• Quantum acoustics unravels Planckian resistivity
• A spatially resolved optical method to measure thermal diffusivity
• Characterization of two electronic subsystems in cuprates through optical conductivity
• The Lorenz ratio as a guide to scattering contributions to Planckian transport

Cited by in corpus (4)

• The Lorenz ratio as a guide to scattering contributions to Planckian transport
• Lorenz ratios of diagonal and Hall conductivities in a Dirac electron liquid
• Multipolar Fermi Surface Deformations in Sr${}_2$RuO${}_4$ Probed by Resistivity and Sound Attenuation: A Window into Electron Viscosity and the Collision Operator
• Low-temperature thermal conductivity of the substrate material YAlO3 and its unconventional sister compound YbAlO3