Large violation of the Wiedemann-Franz law in Heusler, ferromagnetic, Weyl semimetal Co2MnAl

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 Co2MnAl 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.

Automated summary

In this study, researchers found a temperature-dependent violation of the WF law in the Heusler, ferromagnetic, Weyl semimetal Co2MnAl. The extreme magnitude and temperature dependence of the violation in Co2MnAl suggest that there may be multiple effects contributing to the violation in this system.