Large Violation of the Wiedemann Franz Law in Heusler, Ferromagnetic, Weyl Semimetal Co${}_2$MnAl

Abstract

The Wiedemann-Franz (WF) law relates the electronic component of the thermal conductivity to the electrical conductivity in metals through the Lorenz number. The WF law has proven to be remarkably robust, however violations have been observed in many topological materials. In this work, we report thermoelectric measurements conducted on Heusler, ferromagnetic, Weyl semimetal Co${}_2$MnAl which shows a drastic, temperature dependent violation of the WF law below 300 K. We then discuss our result in the context of known physical explanations for WF law violation. Both the magnitude and temperature dependence of the violation in Co2MnAl are extreme, indicating that there may be more than one effect contributing to the violation in this system.

8 pages, 5 figures

References in corpus (6)

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• Anomalous transverse response of Co${}_2$MnGa and universality of the room-temperature ${\alpha }_{ij}^A/{\sigma }_{ij}^A$ ratio across topological magnets
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• Evidence of Weyl Fermion Enhanced Thermal Conductivity Under Magnetic Fields in Antiferromagnetic Topological Insulator Mn(Bi(1-x)Sb(x))2Te4
• Phonon-mediated Hydrodynamic Transport in a Weyl Semimetal
• Resolving the Corbino Shockley-Ramo Paradox for Hydrodynamic Current Noise