Nonlinear theory of the photomagnetoelectric effect with a quadratic relationship between carrier densities: Light intensity dependence

A theory of the photomagnetoelectric (PME) effect in the presence of a recombination mechanism, which involves a quadratic relationship between the carrier densities, is developed. Analytical expressions of PME short-circuit current ($I_{\mathrm{PME}}$) and photoconductance ($\Delta G$) are found by solving the nonlinear continuity equation, in the case in which the light is strongly absorbed on the front surface of the sample. The power law of $I_{\mathrm{PME}}$ versus the light intensity is quadratic for high values of surface-recombination velocity and becomes linear for low values of this parameter. Similarly, the photoconductance has a linear dependence on light intensity for high surface-recombination velocities and a sublinear one for lower values of this last quantity. In all cases the $I_{\mathrm{PME}}-\mathrm{v}\mathrm{s}-\Delta G$ behavior shows a quadratic power law. Finally, the dependence of $I_{\mathrm{PME}}$ and $\Delta G$ on the parameters of the recombination model is discussed.