Giant inverse Faraday effect in Dirac semimetals

Abstract

We have studied helicity dependent photocurrent (HDP) in Bi-based Dirac semimetal thin films. HDP increases with film thickness before it saturates, changes its sign when the majority carrier type is changed from electrons to holes and takes a sharp peak when the Fermi level lies near the charge neutrality point. These results suggest that irradiation of circularly polarized light to Dirac semimetals induces an effective magnetic field that aligns the carrier spin along the light spin angular momentum and generates a spin current along the film normal. The effective magnetic field is estimated to be orders of magnitude larger than that caused by the inverse Faraday effect (IFE) in typical transition metals. We consider the small effective mass and the large $g$-factor, characteristics of Dirac semimetals with strong spin orbit coupling, are responsible for the giant IFE, opening pathways to develop systems with strong light-spin coupling.

References in corpus (10)

• A topological Dirac insulator in a quantum spin Hall phase : Experimental observation of first strong topological insulator
• Theory of spin Hall magnetoresistance
• All-optical control of ferromagnetic thin films and nanostructures
• Quantum Spin Hall Effect and Enhanced Magnetic Response by Spin-Orbit Coupling
• Spin Oscillations in Antiferromagnetic NiO Triggered by Circularly Polarized Light
• Transport Properties and Diamagnetism of Dirac Electrons in Bismuth
• Tunable Giant Spin Hall Conductivities in a Strong Spin-Orbit Semimetal: Bi${}_{1-x}$Sb${}_x$
• Laser-induced torques in metallic ferromagnets
• Interband Effects of Magnetic Field on Hall Effects for Dirac Electrons in Bismuth
• Photoinduced Rashba spin to charge conversion via interfacial unoccupied state