Spin-Polarization in Magneto-Optical Conductivity of Dirac Electrons

TL;DR

This paper proposes a mechanism using the Kubo formula to generate spin-polarized magneto-optical currents in Dirac electron systems with strong spin-orbit coupling, enabling control via circularly polarized light.

Contribution

It introduces a new theoretical approach to induce and control spin-polarized currents in Dirac materials through magneto-optical effects and external magnetic fields.

Findings

Derived selection rules for Dirac electrons under magnetic fields

Demonstrated excitation of spin-polarized electrons using circularly polarized light

Showed potential for spin-polarized current generation in Dirac materials

Abstract

A mechanism is proposed based on the Kubo formula to generate a spin-polarized magneto-optical current of Dirac electrons in solids which have strong spin-orbit interactions such as bismuth. The ac current response functions are calculated in the isotropic Wolff model under an external magnetic field, and the selection rules for Dirac electrons are obtained. By using the circularly polarized light and tuning its frequency, one can excite electrons concentrated in the spin-polarized lowest Landau level when the chemical potential locates in the band gap, so that spin-polarization in the magneto-optical current can be achieved.