Stability diagram of a D− system in quantum dots

Abstract

We report on a theoretical study of a D− system in noncircular quantum dots by an exact diagonalization method. The stability diagram of the D− center is obtained in the presence of perpendicular magnetic fields. At zero magnetic field, it is found that the D− system would disintegrate if the distance between the donor and the edges of the dot is smaller than one effective Bohr radius. In a finite field, the system is always binding when the donor is localized in the center of the dot. As the donor moves away from the center to the edges of the dot, it is seen that the magnetic field would account for the disintegration of the system. The result reveals the interplay between the electron-impurity and electron-electron interactions, quantum confinement, and external magnetic fields in a few-electron system in quantum dots.