Stress effects on the binding energy of shallow-donor impurities in symmetrical GaAs/AlGaAs double quantum-well wires

The effects of applied compressive stress on the binding energies of shallow-donor impurity states with a finite confinement potential in symmetrical GaAs/AlGaAs double quantum-well wires (DQWWs) are studied theoretically using a variational procedure within the effective-mass approximation. Significant results for different wire and barrier widths, shallow-donor impurity positions, and compressive stress along the growth direction of the structure are obtained taking into account the Γ-X crossover and the image charge effects in the calculations. Our results show that the binding energy does not change appreciably with the size of the wire and barrier, or with the donor ion position. We also find that for stress values up to 13.5 kbar, the binding energy increases linearly with stress, while for stress values greater than 13.5 kbar, the binding energies show nonlinear behavior. Moreover, in the limit of double quantum wells (DQWs), our binding energy agrees with previously reported results. It is pointed out that compressive stress is an important factor in studies of the binding energies of shallow-donor impurity states in symmetrical GaAs/AlGaAs DQWWs