On-center donor impurity-related nonlinear corrections to optical absorption and refractive index in a two-dimensional quantum ring

Abstract

The donor impurity-related linear and nonlinear optical absorption as well as the linear and nonlinear corrections to the refractive index in a disc-shaped quantum dot under the effect of an external magnetic field and parabolic and inverse square confining potentials are calculated making use of the exact solutions for the two-dimensional motion of a conduction band electron in the system. It has been previously shown that this kind of structure may work well as a model for a quantum ring. In general terms, for a fixed confining configuration and the basic parameters typical of GaAs, the influence of an on-center donor impurity reflects in a blueshift of the resonant peak positions, together with a reduction in the peak amplitudes, affecting more significantly the nonlinear contributions. The results also show that the influence of the normally oriented magnetic field induces a blueshift in both the first and third order peaks of the calculated optical quantities. In addition, total peak amplitudes are shown to be growing functions of the magnetic field strength. The increase in the strength of the inverse square potential function enhances significantly the contribution from the nonlinear third-order terms in both the absorption and the relative correction to the refractive index.