Magnetic field-Induced Nonlinear Optical Responses in Inversion Symmetric Dirac Semimetals

TL;DR

This paper demonstrates that external magnetic fields can induce nonlinear optical effects, such as photogalvanic and second harmonic generation, in inversion-symmetric Dirac semimetals due to magnetochiral effects.

Contribution

It reveals a new mechanism for nonlinear optical responses in Dirac semimetals driven by magnetic fields and band bending effects.

Findings

Magnetic fields induce photogalvanic effects in Dirac semimetals.

Second harmonic generation can be activated by magnetic fields.

Observable surface dc currents and polarization rotation occur under irradiation.

Abstract

We show that, under the effect of an external magnetic field, a photogalvanic effect and the generation of second harmonic wave can be induced in inversion-symmetric and time reversal invariant Dirac semimetals. The mechanism responsible of these non linear optical responses is the magnetochiral effect. The origin of this magnetochiral effect is the band bending of the dispersion relation in real Dirac semimetals. Some observable consequences of this phenomenon are the appearance of a dc current on the surface of the system when it is irradiated with linearly polarized light or a rotation of the polarization plane of the reflected second harmonic wave.