Nonlinear magneto-optical response across van Hove singularity in a non-centrosymmetric magnetic Weyl semimetal

Abstract

We investigate the nonlinear magneto-optical response in non-centrosymmetric magnetic Weyl semimetals featuring a quadratic tilt, focusing particularly on the influence of the van Hove singularity (VHS). In the absence of a magnetic field, the second-order nonlinear Drude conductivity components exhibit inflection or dip behavior across the VHS. In contrast, the second-order nonlinear anomalous Hall conductivity, primarily governed by the Berry curvature dipole, manifests a subtle plateau-like structure. As the tilt strength increases, the VHS energy escalates, thereby amplifying the VHS-induced characteristics within these second-order conductivity components. However, in the presence of a magnetic field, we show that the resultant magnetic moment suppresses nonlinear electron transport while enhancing nonlinear hole transport. %both suppresses and notably enhances nonlinear magnetic-optical transport in the electron and hole regions, respectively. This effect serves to mitigate the impact of the VHS, resulting specifically in an asymmetric peak or a kinked-like structure in the magnetic field-induced contribution to the second-order nonlinear conductivity near the Weyl nodes. These findings provide new insights into the intricate interplay among the VHS, Berry curvature, and magnetic moment in nonlinear magneto-optical transport through non-centrosymmetric magnetic Weyl semimetals.