Exciton-phonon interaction and phonon frequency renormalization in semiconductor quantum dots

We present a theory of LO phonon renormalization by coupling with the excit on in semiconductor quantum dots. We find that the one phonon side band of the exciton ground state shows an anticrossing with the excited exciton sta tes. Across such an anticrossing, the phonon-like and exciton-like modes ex change their characters resulting in a redistribution of the oscillator str engths of interband transitions. Even away from such a resonant coupling, t he phonon frequency shift is significant. For example, in CuCl quantum dots in the weak confinement regime, the phonon frequency in the presence of a single exciton is reduced by about 10% from its value in the ground state.