Effect of a charged impurity on a lithium quantum dot

A lithium quantum dot (QD) with a charged impurity is studied, where the charged impurity is located on the z-axis at a distance d from the lithium QD plane (the x-y plane). Using the method of few-body physics, the energy spectra of the low-lying states of the QD are obtained as a function of d. It is found that the energy spectra depend strongly on both the position and charge of the impurity. Furthermore, the impurity affects the electronic configurations of the QD, i.e. the spatial distribution of the electrons of the QD. Our calculations indicate that the change of d induces transitions in the ground states of the QD, which can be explained by dynamics and symmetry.