Research on Topological Nonlinear Thermoelectric Response Theory, Higher-Order Mott Relations, and the Wiedemann-Franz Law

Ordinarily, physical quantities related to electrical and thermal transport are linear response tensors. Nonlinear response-related physical quantities are considered small and have not been systematically studied. In 2015, Sodemann and Fu proposed the nonlinear Hall effect, describing that in systems with time-reversal symmetry, under the drive of an applied time-varying alternating electric field, the linear Hall effect vanishes, but a non-zero nonlinear Hall current arises due to the breaking of spatial inversion symmetry. Its microscopic origin is associated with the Berry curvature dipole in momentum space. This reveals a special relationship between band topological properties and nonlinear transport. In this lecture, several works in the direction of topological nonlinear thermoelectric transport will be introduced, including the nonlinear anomalous Nernst effect, the quantum theory of nonlinear thermoelectric response, as well as higher-order Mott relations and the Wiedemann-Franz law.

Zhu Zhengang is a Professor at the University of Chinese Academy of Sciences (UCAS) and a recipient of the "BR" Program of the Chinese Academy of Sciences (CAS). He has presided over major national R&D programs, key and general projects of the National Natural Science Foundation of China (NSFC), and is a recipient of the Special Government Allowance of the State Council.

His main research interests include topological properties, quantum transport, spintronics and devices, two-dimensional novel materials, and theoretical research on strongly correlated systems. He has published more than 90 academic papers in international mainstream journals such as Physical Review Letters, Advanced Materials, and Physics Reports.