Polaron effect on the binding energies of excitons in quantum wells under hydrostatic pressure

Abstract

AbstractUnder hydrostatic pressure, the polaron effect on the binding energies of excitons in quantum wells is discussed by a variational method by considering the influence of finite barriers and the coupling of an exciton with bulk confined longitudinal optical, half space longitudinal optical and interfacial optical modes. A quasi‐ two dimensional Lee‐Low‐Pines like unitary transformation is adopted to deal with the exciton‐phonon interaction and the pressure dependence of physical parameters is also taken into account in the calculation. As an example, the numerical computation is applied to the GaAs/Alx Ga1–x As quantum wells. The result shows that the exciton binding energies increase with presure from 0 to 40 kbar. The maximum energy shift is about 21% for the given quantum well width and Al concentration x = 0.15. The exciton‐phonon interaction energies also increase with pressure and the effects of three kinds of different exciton‐phonon interactions are discussed in detail for different widths of quantum wells. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)