The Lorenz number in CeCoIn${}_5$ inferred from the thermal and charge Hall currents

Abstract

The thermal Hall conductivity ${\kappa }_{xy}$ and Hall conductivity ${\sigma }_{xy}$ in CeCoIn${}_5$ are used to determine the Lorenz number ${\mathcal{L}}_H$ at low temperature $T$. This enables the separation of the observed thermal conductivity into its electronic and non-electronic parts. We uncover evidence for a charge-neutral, field-dependent thermal conductivity, which we identify with spin excitations. At low $T$, these excitations dominate the scattering of charge carriers. We show that suppression of the spin excitations in high fields leads to a steep enhancement of the electron mean-free-path, which leads to an interesting scaling relation between the magnetoresistance, thermal conductivity and ${\sigma }_{xy}$.

6 pages, 7 figures Intro para slightly lengthened. Added 2 new ref

References in corpus (2)

• Nonvanishing Energy Scales at the Quantum Critical Point of CeCoIn5
• Anomalous thermopower and Nernst effect in $\mathrm{CeCoI}{\mathrm{n}}_5$: entropy-current loss in precursor state

Cited by in corpus (3)

• Hall effect in heavy-fermion metals
• Apparent Violation of the Wiedemann-Franz law near a magnetic field tuned metal-antiferromagnetic quantum critical point
• Hybridization-Controlled Pseudogap State in the Quantum Critical Superconductor CeCoIn5