Photonic spin Hall effect dependent on Landau level transitions in monolayer WTe2

Abstract

Landau level (LL) engineered photonic spin Hall effect (PSHE) holds great promise for nanoscale manipulation and steering of magneto-optical transport in two-dimensional atomic systems. Herein, we theoretically investigate PSHE modulated by LL transitions {\delta}n = n'-n =-2, 0, +2 (where n and n' indicate the LL indexes of valence and conduction bands, respectively) in monolayer WTe2. Results show that PSHE tuned by {\delta}n =-2, 0, +2 has completely different dependent behaviors on LLs, incident angle of incident photons, and magnetic induction intensity. These discrepancies are ascribed to Hall-conductivity-incurred Hall angle {\Theta} because the variation tendency of photonic spin Hall shifts is similar to that of {\Theta} with changing the LL index. Giant PSHE with the largest in-plane displacement of more than 400 times of incident wavelength is obtained at the transition |n=55>->|n'=57>. Remarkably enhanced PSHE occurs at near-zero Hall angles. In-plane and transverse spin-dependent displacements give their respective extremum values at the same incident angles when the {\Theta} is near to zero, and their incident-angle deviation will become larger and larger as the |{\Theta}| increases. This unambiguously confirms the strong influence of Hall angle in the PSHE, shedding important insights into the fundamental properties of spin-orbit interaction of light in time-reversal symmetry breaking quantum systems.