Binding energy of impurity states in a parabolic quantum dot in a strong magnetic field

The binding energies of shallow hydrogenic impurities in parabolic quantum dots are calculated using a variational approach within the effective mass approximation. Results are obtained for Cd1-xinMnxinTe/Cd1-xoutMnxoutTe structures as a function of the dot radius in an external magnetic field. The results show that the impurity binding energy (i) increases with the decrease in dot radius, (ii) decreases when the magnetic field is increased for a given dot and (iii) increases to a maximum value at 90 angstrom and then decreases as the size of the dot increases beyond 90 angstrom in the finite barrier case. This feature is different from non magnetic quantum well structures. Spin polaronic shifts are estimated using a mean field theory. The results show that the shifts are <= 1 meV in the zero-field case and still smaller in a magnetic field. This shift not only decreases in a magnetic field but also decreases when the dot radius increases. (c) 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.