Valley-spin polarization in the magneto-optical response of square lattice

In this work, we try to investigate the magneto-optical response of the square lattice model, in which the quantum spin Hall effect will occur when spin is introduced to the anisotropy next-nearest-neighboring hoppings. In the presence of Landau level quantization, we analyze the optical absorption spectrum and reveal the valley-spin polarization of the electrons when the total filling factor in the system changes. We also study the optical Hall conductivity behavior to find the signatures of valley-spin polarization. The implications of our results are discussed. Copyright EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg 2014