Dynamics of electron impurity doped quantum dots in the presence of time-varying fields: Influence of impurity location

We explore the pattern of time evolution of eigenstates of a repulsive impurity doped quantum dot. The quantum dot is two dimensional and contains one electron which is harmonically confined. We have considered Gaussian impurity centers. A static transverse magnetic field is also present. For given strength of confining fields, intensity and oscillation frequency of external time-varying field, the system reveals a long time dynamics that is undulatory in nature. The location of impurity at on and off-center positions prominently affects the eigenstates of the unperturbed system and consequently the nature of the dynamics. Separations between various energy levels and corresponding transition moment values as a function of impurity position are invoked to explain the dynamical features. The Fourier transform of time evolution profiles indicates the role of collective excitations towards population build up in some particular states. (C) 2010 Elsevier B.V. All rights reserved.