The role of interface phonons in the formation of polaron states in quantum wells

A theory of a large-radius polaron in a quantum well is developed with consideration of the interaction of charged particles with different branches of the phonon spectrum. It is shown that, in narrow quantum wells, the major contribution to the polaron binding energy is made by interaction with symmetric interface phonons. As a result of such interaction, the polaron binding energy is defined by the effective mass of charge carriers in the quantum well and by the polarization properties of barriers. The possibilities of the formation of a polaron exciton in a quantum well in the case of strong interaction of charged particles with optical phonons are analyzed. The conditions in which the polarization fields produced by the electron and hole do not substantially compensate each other are established.