Wiedemann-Franz law for massless Dirac fermions with implications for graphene

Abstract

In the 2016 experiment by Crossno et al. [Science 351, 1058 (2016)], electronic contribution to the thermal conductivity of graphene was found to violate the well-known Wiedemann-Franz (WF) law for metals. At liquid nitrogen temperatures, the thermal to electrical conductivity ratio of charge-neutral samples was more than 10 times higher than predicted by the WF law, what was attributed to interactions between particles leading to collective behavior described by hydrodynamics. Here we show, by adapting the handbook derivation of the WF law to the case of massless Dirac fermions, that significantly enhanced thermal conductivity should appear also in few- or even sub-kelvin temperatures, where the role of interactions can be neglected. The comparison with numerical results obtained within the Landauer-Büttiker formalism for rectangular and disk-shaped (Corbino) devices in ballistic graphene is also provided.

Minor revisions; Refs. added. RevTeX, 12 pages, 9 figures

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Cited by in corpus (11)

• Sub-Sharvin conductance and enhanced shot noise in doped graphene
• Thermoelectric properties of inversion symmetry broken Weyl semimetal-Weyl superconductor hybrid junctions
• Theory of the sub-Sharvin charge transport in graphene disks
• Thermoelectric properties of the Corbino disk in graphene
• Thermoelectric properties and Wiedemann-Franz like relations in mixed-dimensional QEDs from particle-vortex dualities
• Wiedemann-Franz law violation domain for graphene and nonrelativistic systems
• Sub-Sharvin conductance and incoherent shot-noise in graphene disks at magnetic field
• Transport in honeycomb lattice with random $\pi$-fluxes: implications for low-temperature thermal transport in the Kitaev spin liquids
• On the Wiedemann-Franz law violation in Graphene and quark-gluon plasma systems
• Quantum transport of Dirac fermions in selected graphene nanosystems away from the charge-neutrality point
• Charge and energy transport in graphene with smooth finite-range disorder