Nonlinear transport in Weyl semimetals induced by Berry curvature dipole

Topological Weyl semimetals (WSMs) have been predicted to be excellent candidates for detecting Berry curvature dipole (BCD) and the related nonlinear effects in electronics and optics due to the large Berry curvature concentrated around the Weyl nodes. And yet, linearized models of isolated tilted Weyl cones only realize a diagonal nonzero BCD tensor which sum to zero in the model of WSM with multiple Weyl nodes in the presence of mirror symmetry. On the other hand, recent ab initio work has found that realistic WSMs like TaAs-type or MoTe2-type compounds, which have mirror symmetry, indeed show an off-diagonal BCD tensor with an enhanced magnitude for its nonzero components. So far, there is a lack of theoretical work addressing this contradiction for three-dimensional (3D) WSMs. In this paper, we systematically study the BCD in 3D WSMs using lattice Weyl Hamiltonians, which go beyond the linearized models. We find that the nonzero BCD and its related important features for these WSMs do not rely on the contribution from the Weyl nodes. Instead, they are dependent on the part of the Fermi surface that lie between the Weyl nodes, in the region of the reciprocal space where neighboring Weyl cones overlap. For large-enough chemical potential, such Fermi surfaces are present in the lattice Weyl Hamiltonians as well as in the realistic WSMs. We also show that a lattice Weyl Hamitonian with a nonzero chiral chemical potential for the Weyl cones can also support dips or peaks in the off diagonal components of the BCD tensor near the Weyl nodes themselves, consistent with recent ab initio work. In addition, we predict specific experimental signatures of BCD-induced transport such as nonlinear anomalous Hall, Nernst, and thermal Hall effects in WSMs that can be directly checked in experiments.

Automated summary

This study systematically investigates the BCD in 3D WSMs using lattice Weyl Hamiltonians and finds that the nonzero BCD and its related important features are not dependent on the contribution from the Weyl nodes, but rather on the part of the Fermi surface lying between the Weyl nodes. Additionally, specific experimental signatures of BCD-induced transport in WSMs, such as nonlinear anomalous Hall, Nernst, and thermal Hall effects, are predicted and can be directly checked in experiments.