STRONG-CONFINEMENT APPROACH FOR IMPURITIES IN PARABOLIC QUANTUM DOTS

The strong-confinement approach for the study of electronic properties of semiconductor quantum dots has been generalized to the case of dot s defined by a parabolic confining potential. The ground and lowest-ty ing excited states of a donor impurity located anywhere in the quantum dot and subject to magnetic fields have been analyzed with this gener alized approach. The impurity-related binding energy depends strongly on impurity position in the dot and magnetic field strength. While mos t cases the impurity binding energy exhibits the expected decrease wit h the distance between the dot center and impurity coordinate, the low est-lying excited states at small fields first increase their binding energies when the impurity moves away from the dot center, reach a max ima, and then decrease.