Polaronic effect on the binding energy of an impurity with varying position in parabolic quantum dots

The Feynman-Haken variational path integral theory is generalized to calcul ate the binding energy E-b Of an electron coupled simultaneously to an impu rity with varing position and to a longitudinal-optical (LO) phonon field i n parabolic quantum dots. Our calculations are applied to some semiconducto r materials and the results for the binding energy are obtained for differe nt confinement length R of the dot and arbitrary position of the impurity. It is shown that the polaronic correction to E-b decreases with the displac ement of the impurity and increases with the confinement length of the dot. More interestingly, it is not so strong as the polaronic correction to the ground-state energy of the system, and the behaviours of their variation w ith R are totally different. (C) 1999 Elsevier Science B.V.