Renormalization of energy spectrum of quantum dots under vibrational resonance conditions

Abstract

The problem of modification of the energy spectrum of electronic and phonon excitations in semiconductor quantum dots (QDs) under conditions of vibrational resonance is considered. Analytical expressions for the energy of polaron-like states in QDs in the form of a sphere or rectangular parallelepiped, taking into account the size dependence of the electron-phonon interaction, are derived. Experimental data on renormalization of the lowest exciton states in QDs based on CuCl in a NaCl matrix have been obtained with the use of two-photon secondary emission resonance spectroscopy. Comparison with the calculated results demonstrates quantitative agreement indicating the adequacy of the employed theoretical model. It is established that the vibrational resonance strongly modifies the energy spectrum of small QDs.