Surface states-dependent giant quantized photonic spin Hall effect in a magnetic topological insulator thin film

Abstract

We theoretically investigate the in-plane and transverse photonic spin Hall effect (PSHE) in a magnetic topological ultra-thin film (MTF) in the terahertz regime in the presence of an external magnetic field. We take into account the hybridization between the top and bottom surface states (SSs) and demonstrate that both the in-plane and transverse PSHE are quantized due to the Landau levels (LLs) quantization of the magneto-optical (MO) conductivities. The interplay between the effective energy induced by the hybridization interaction and the Zeeman energy plays an important role as it results in topological and normal insulating phases. By manipulating the interplay between these two interaction energies we drive the system through several topological quantum phase transitions (TQPTs). We show that the PSHE can be greatly enhanced and the magnitude of the giant PSHE in MTF is several hundreds times of the incident gaussian beam wavelength. Furthermore, we show that the PSHE is sensitive to the SSs of the Dirac fermions which is due to its topological character. This work sheds important light both on the PSHE and on the MO transport properties in MTFs in the presence of an external magnetic field which harbor great potentials in the development of new-generation photonics spin-Hall and optoelectronic devices.