Effects of impurity on the energy spectra of quantum-dot lithium

In this work, the effects of an off-center attractive Gaussian impurity on the ground-state energy and spin properties of parabolic quantum-dot lithium are investigated with Configuration Interaction Method. Phase transition between spin-1/2 and spin-3/2 states of the system is obtained for various strengths of the impurity potential and the electron–electron interaction. Charge densities of the system are studied in different interaction regimes. Numerical results reveal that the gap between two spin states is increased by the impurity which consequently yields to the suppression of the polarization.