Effects of interface and bulk optical phonons on polarons in a quantum well

The properties of a confined electron interacting with both the confined longitudinal optical (LO) and interface optical (IO) phonons in a quantum well (QW) are investigated. By using a modified Lee-Low-Pines variational method, an analytical expression for the polaron ground-state energy is obtained. Numerical calculation is performed for a GaAs/AlAs QW as a typical case. The results show that only two symmetric IO-phonon modes as well as the confined LO-phonon mode contribute to the energies of the polaron. It is also found that one of the symmetric IO-phonon modes is more important, its contribution to the energies is much larger than the others when the QW width is smaller than the polaron radius.