Interaction of electrons with polaritons

Abstract

The electromagnetic (EM) waves associated with the polariton modes of bulk dielectrics are quantized using a procedure that accounts for both the EM and matter fields. The interaction of electrons with these polariton fields is described using the minimal coupling (e/m*)A.p interaction Hamiltonian where A is the transverse vector potential operator of the polariton field, p the electronic momentum and m* its effective mass. The electron-polariton interaction in the bulk is demonstrated to be closely linked to the behaviour of the polariton group and phase velocities. The same quantization procedure is then employed to describe the EM fields associated with the interface polaritons of a GaAs/AlAs quantum well system. The coupling leads to a dependence of the scattering rate on the group and phase velocities of the surface modes, just as it does for the bulk excitations. In contrast to the case in the bulk, it is shown that these modes are important for relaxing the electron energy in narrow wells.