Bound polaron in a polar semiconductor heterojunction

The behavior of an optical polaron bound to a donor impurity near the interface of a polar semiconductor heterojunction is investigated with a variational method by considering the influence of a realistic heterojunction potential, the electron-phonon and impurity-phonon interactions, including the effect of half-space bulk longitudinal and interface-optical phonon modes. The bound-polaron binding energy is computed for GaAs/AlxGa1-xAs (0.2<x<0.4) heterojunction system. The result shows that the impurity-phonon interaction is important and that the phonon contribution to the binding energy is negative. Both of the bulk longitudinal and interface-phonon modes give important contributions to the binding energy when the impurity is located in GaAs. The interface modes are more important than the bulk-phonon modes when the impurity is located in AlxGa1-xAs. [S0163-1829(99)06103-2].