Berry curvature induced thermopower in type-I and type-II Weyl semimetals

Abstract

Berry curvature acts analogous to a magnetic field in the momentum-space, and it modifies the flow of charge carriers and entropy. This induces several intriguing magnetoelectric and magnetothermal transport phenomena in Weyl semimetals. %, including the planar Hall and planar Nernst effect. Here, we explore the impact of the Berry curvature and orbital magnetization on the thermopower in tilted type-I and type-II Weyl semimetals, using semiclassical Boltzmann transport formalism. We analytically calculate the full magnetoconductivity matrix and use it to obtain the thermopower matrix for different orientations of the magnetic field $(B)$, with respect to the tilt axis. We find that that the tilt of the Weyl nodes induces linear magnetic field terms in the conductivity matrix, as well as in the thermopower matrix. The linear-$B$ term appears in the Seebeck coefficients, when the $B$-field is applied along the tilt axis. Applying the magnetic field in a plane perpendicular to the tilt axis results in a quadratic-$B$ planar Nernst effect, linear-$B$ out-of-plane Nernst effect and quadratic-$B$ correction in the Seebeck coefficient.