Faraday rotation in antiferromagnetic silicene

Abstract

In this work, we explore theoretically the Faraday rotation and magneto-optical conductivity in silicene in the presence of antiferromagnetism and vertical electric and magnetic fields. The interplay between the intrinsic strong Kane–Mele spin–orbit coupling in low-buckled silicene, externally applied electric and antiferromagnetic fields, leads to topological phase transitions. We show that the application of perpendicular electric and antiferromagnetic fields results in the emergence of a quantum spin Hall insulator (QSHI), a spin quantum anomalous Hall insulator, a charge density wave, and anti-ferromagnetic insulator states. We obtain analytical formulas for the valley- and spin-dependent magneto-optical conductivities using the Kubo formalism. The longitudinal and transverse Hall conductivities are investigated vs incident photon energy for different magnetic, electric, and antiferromagnetic fields. We also demonstrate that a large Faraday rotation of 4.5° is obtained in silicene in the QSHI at 5 T.