Anomalous circular photogalvanic effect of the spin-polarized two-dimensional electron gas in Mg0.2Zn0.8O/ZnO heterostructures at room temperature

A spin-related photocurrent with swirly distribution and anomalous dependence of the total spin-related photocurrent on the incident angle were observed on spin-polarized two-dimensional gas in a Mg ₀.₂ Zn ₀.₈O/ZnO heterostructure under illumination of circular polarized light at room temperature. The ferromagnetic two-dimensional Rashba model was adopted to interpret the results. It is demonstrated that a radial spin current induced by the gradient of the spin-polarized electron density is the origin of the anomalousness. This spin current only exists in spin polarized systems.This work was supported by National Basic Research Program of China (Nos. 2012CB921304 and 2012CB619306), the National Natural Science Foundation of China (Nos. 60806042, 11174008, and 60990313), the Wuhan National High Magnetic Field Center (WHMFCKF2011004), the Australian Research Council Discovery Project Grant (DP1096918), and Basic Research Program of Jiangsu Province (BK2011437)