C 1 ′ and C 2 ′ are background currents. To fit the photocurrent curves when the linearly polarized direction of the incident light is along [1 0], [110], [100] and [010] selleck compound crystallographic directions, selleck chemicals llc respectively, we find that parameters S 1, S 1 ′ and S 1 − are considerably larger than parameters S 2, S 2 ′, S 2 ±, S 3, S 3 ′ and S 3 ±. The detailed fitting

results of the parameters are listed in Table 1. This reveals that polarization independent currents are dominant in total magneto-photocurrents. Furthermore, we found that the parameters S 1 and S 1 ′ are slightly smaller than S 1 −. The polarization-independent currents present anisotropy of crystallographic directions. The parameters of linearly polarized light-induced photocurrents are in the same order of magnitude except the S 3 is larger. Table 1 Fitting selleck kinase inhibitor results of the parameters   Value S 1 5.535 S 2 −0.015 S 3 0.383 S 1 ′ −5.241 S 2 ′ −0.003 S 3 ′ 0.018 S 1 + 0.269 S 1 − −6.093 S 2 + −0.016 S 2 − −0.015 S 3 +

0.002 S 3 − −0.018 Units: . From the microscopic point of view, the electric photocurrent density can be calculated by summing the velocities of the photo-excited carriers. The magneto-photocurrent in μ direction (μ=x,y) can be described by [5, 22] (5) e is the electron charge. denotes the electron velocity along μ direction. In the excitation process, is the steady-state nonequilibrium photo-excited electron density in Zeeman-splitting conduction bands. It can be described by Equation 6 for the linearly polarized radiation. (6) ϕ is the angle between the wave vector and the x direction. α is the angle between the plane of linear polarization and the x direction. Considering the contribution of asymmetric relaxation of electrons to the current, we should

add an additional term to the . Then the in Equation 6 includes contributions Cell press of both excitation and relaxation. Owing to the magneto-photocurrent in this superlattice is independent of the radiation polarization, it can be deduced that is much larger than and . This conclusion is similar to that in [22] which that reported always overwhelms and theoretically. The radiation polarization independent of MPE generated by direct interband transition had also been observed in the BiTeI film [23]. However, in (110)-grown GaAs/Al x Ga 1−x As quantum wells, MPE generated by indirect intrasubband transition shows clear relations to the radiation linear polarization state [24]. The reason may be that in the intrasubband transition process, spin-dependent asymmetric electron-phonon interaction which contributes to the magneto-photocurrent is sensitive to the radiation polarization state. It leads to the relative magnitudes of and in Equation 6 increase. More practically, the phonon effect may be taken into account when designing optically manipulated spintronics devices in the future.