Nonlinear planar Nernst effect in magnetic topological insulator heterostructures

A new nonlinear magnetothermal effect, namely nonlinear planar Nernst effect (NPNE), has been recently predicted in nonmagnetic topological insulators and Weyl semimetals. Both of the asymmetric energy dispersion and the in-plane magnetic field play significant roles in the reported materials. Here, we prove that the NPNE can also be generated in magnetic/nomagnetic topological heterostructures in the presence of an in-plane magnetization and in the absence of asymmetric energy dispersion. It is found that the NPNE has a quantum origin from the asymmetric magnon scattering and exhibits a cosine dependence on the orientation of the magnetization with respect to the direction of the temperature gradient ($x$ direction).