Combined effects of hydrostatic pressure and electric field on the donor binding energy, polarizability, and photoionization cross-section in double GaAs/Ga $$_{1-x}$$ 1 - x Al $$_{x}$$ x As quantum dots

The present work focuses on the theoretical calculations of the ground-state binding energy of a shallow impurity, the impurity-related photoionization cross-section (PICS), and impurity-related polarizability under the combined effects of an electric field and hydrostatic pressure using a variational approach within the parabolic-band and effective-mass approximations. The low heterostructure is made up of two GaAs quantum dots separated by a Al $$_{0.3}$$ 0.3 Ga $$_{0.7}$$ 0.7 As central barrier. The applied electric field is considered to be directed along the growth-direction. As a general, the binding energy is obtained as a function of the impurity position and the electric field intensity. The PICS is calculated as a function of photon energy, for various impurity positions, with changes in hydrostatic pressure and/or electric field strength to prove their impact on their magnitude and shifting. Calculations are without accounting for the $$\Gamma -X$$ Γ - X effect of the GaAs/Al $$_{0.3}$$ 0.3 Ga $$_{0.7}$$ 0.7 As and for a specific nanostructure size. In addition, we have shown how variations in hydrostatic pressure and electric field affect the polarizability of impurities at three distinct places in the nanostructure. Graphical abstract