Preferred ground states of a quantum dot under a strong magnetic field

The ground-state energies of several interacting electrons confined in a pa rabolic dot in two dimensions are obtained by using hyperspherical coordina tes and high-order perturbation theory. The effect of a perpendicular magne tic field is to change the ground state discontinuously in orbital angular momentum L. The preferred values of L for the ground state and the associat ed electronic structures are studied in detail. It is found that the effect ive interaction between two electrons moving in different cyclic orbits is a short-range attraction matched to a long-range repulsive tail. Because of this, electrons tend to fill adjacent cyclic orbits and form bunches in th e ground states. The effects of an impurity ion are also considered.