Nonlinear chiral photocurrent in parity-violating magnetic Weyl semimetals

TL;DR

This paper investigates the nonlinear chiral photocurrent in parity-violating magnetic Weyl semimetals, revealing how magnetic texture dynamics influence photocurrent responses and magnetization orientation, with potential applications in spintronics.

Contribution

It introduces a theoretical framework for understanding the chiral photocurrent in magnetic Weyl semimetals, highlighting the role of magnetic texture and parity violation in nonlinear optical responses.

Findings

Chiral photocurrent can rotate magnetization from c to a/b axes.

Resonant photocurrent magnitude is on the order of mA/W near Weyl nodes.

Magnetic texture dynamics strongly influence the magnitude and orientation of the photocurrent.

Abstract

The strong correlation between the non-trivial band topology and the magnetic texture makes magnetic Weyl semimetals excellent candidates for the manipulation and detection of magnetization dynamics. The parity violation together with the Pauli blocking cause only one Weyl node to contribute to the photocurrent response, which in turn affects the magnetic texture due to the spin transfer torque. Utilizing the Landau-Lifshitz-Gilbert equation and the spin-transfer torque in non-centrosymmetric Weyl magnets, we show that the chiral photocurrent rotates the magnetization from the easy c axis to the a or b axis, which leads to an exotic current next to the photocurrent response. The chiral photocurrent is calculated in the context of quantum kinetic theory and it has a strong resonance on the order of mA/W near the Weyl nodes, the magnitude of which is controlled by the momentum relaxation time. Remarkably, we study the influence of magnetic texture dynamics on the topological nonlinear photocurrent response, including shift and injection currents along with the new chiral photocurrent, and show that both the magnitude and the in-plane orientation of the chiral photocurrent are strongly correlated with the direction of the magnetic moments.