Giant Berry curvature dipole density in a ferroelectric Weyl semimetal
Cheng-Long Zhang, Tian Liang, Y. Kaneko, Naoto Nagaosa, Yoshinori Tokura
Abstract
Abstract The nonlinear Hall effect (NLHE) reflects Berry-curvature-related properties in non-centrosymmetric but time-reversal-symmetric materials. So far, the NLHE of the investigated systems remains a tiny effect due to the lack of Weyl point as magnetic monopoles in 2D systems or to the high carrier concentration in 3D systems. Here, we report large NLHE due to gigantic Berry curvature dipole density as generated by tilted Weyl cones near the Fermi level in a model ferroelectric Weyl semimetal In-doped Pb 1 −x Sn x Te. By systematically lowering the carrier concentration down to ~10 16 cm −3 , the Berry curvature dipole density reaches values around 10 −21 m 3 , 10 2 –10 7 times higher than the previously reported ones. Furthermore, NLHE exhibits a power law of carrier concentration and follows the k −2 relation of the Berry curvature expression derived from the monopole. The present study establishes giant NLHE in a ferroelectric Weyl semimetal, promising for future applications such as current rectification.