Event

Topological Weyl semimetals provide a new stage to examine exotic transport phenomena such as the chiral anomaly and the anomalous Hall effect. In the ordinary longitudinal transport, the Wiedemann-Franz law links the ratio of electronic charge and heat conductivity to fundamental constants. It has been tested in numerous solids, but the extent of its relevance to the anomalous transverse transport, which represents the topological nature of the wave function, remains an open question. In this talk, I will first introduce recently-discovered Weyl materials Mn3Sn and Mn3Ge. Their noncollinear chiral spin structure induces huge anomalous Hall effect. Then I will talk about our recent work on the thermal Hall effect, in collaboration with the experiment. We reveal a finite temperature violation of the Wiedemann-Franz correlation. This is caused by the different relation to the Berry curvature between the charge and thermal Hall effect, rather than the inelastic scattering as observed in ordinary metals.  

Bio: Binghai Yan has been working on the prediction of topological materials. He is also interested in the topology-induced transport and optical properties. In 2008, he received his PhD in physics at the Tsinghua University.  After that, he worked as a Humboldt postdoc in Germany and a postdoc in Stanford University. In 2012, he became a group leader in the Max Planck Institute in Dresden, Germany. Since 2017, he is an assistant professor at the Weizmann Institute of Science, Israel. He was awarded the Israel Physical Society Prize for Young Scientist in 2017.