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 dots defined by a parabolic confining potential. The ground and lowest-tying excited states of a donor impurity located anywhere in the quantum dot and subject to magnetic fields have been analyzed with this generalized approach. The impurity-related binding energy depends strongly on impurity position in the dot and magnetic field strength. While most cases the impurity binding energy exhibits the expected decrease with the distance between the dot center and impurity coordinate, the lowest-lying excited states at small fields first increase their binding energies when the impurity moves away from the dot center, reach a maxima, and then decrease.