Optical absorption of a many-polaron system confined in a quantum dot

The ground state energy and the optical absorption spectra are obtained for N electrons interacting with each other and with the longitudinal optical (LO) phonons at an arbitrary electron-phonon coupling strength in a parabol ic confinement potential. In order to account for the fermion statistics, w e use the path integral formalism for identical particles. The approach is at present limited to closed shells. In the case of strong electron-phonon interaction, a ferromagnetic-to-nonmagnetic transition is shown to occur be tween states with different total spin of the system. This transition is re vealed through the optical absorption spectra and should be experimentally observable. When the confinement frequency parameter is in resonance with t he LO phonon frequency, strong mixing between zero-phonon and one-phonon st ates is manifested in the absorption spectrum. (C) 2000 Elsevier Science Lt d. All rights reserved.