Finite-temperature violation of the anomalous transverse Wiedemann-Franz law
Liangcai Xu, Xiaokang Li, Xiufang Lu, Clément Collignon, Huixia Fu, Jahyun Koo, Benoît Fauqué, Binghai Yan, Zengwei Zhu, Kamran Behnia
Abstract
Ge extended from room temperature down to sub-kelvin temperature and find that the anomalous Lorenz ratio remains close to the Sommerfeld value up to 100 K but not above. The finite-temperature violation of the WF correlation is caused by a mismatch between the thermal and electrical summations of the Berry curvature and not by inelastic scattering. This interpretation is backed by our theoretical calculations, which reveals a competition between the temperature and the Berry curvature distribution. The data accuracy is supported by verifying the anomalous Bridgman relation. The anomalous Lorenz ratio is thus an extremely sensitive probe of the Berry spectrum of a solid.