Effects of hill-like and inverse parabolic electric potentials on photoionization cross-section, diamagnetic susceptibility and binding energies in spherical quantum dots

We have theoretically investigated effects of hill-like parabolic and inverse parabolic electric confining potentials on the photoionization cross-section (PCS), diamagnetic susceptibility (DMS), and binding energies of donor impurity-bound electron states located at the center of spherical GaAs quantum dots (SQDs). The results reveal that the inverse parabolic potential draws electron density toward the quantum dot boundaries, thereby reducing binding energies and increasing the magnitude of the DMS, while the hill-like potential enhances ground-state binding energies, decreases excited-state binding energies, and modulates DMS in a state-dependent manner. Additionally, the hill-like potential causes blueshifts in resonance peaks of PCS for \(1s\rightarrow 2p\) transitions and redshifts for \(2p \rightarrow 3d\), whereas the inverse potential consistently causes redshifts for all transitions. A linear combination of the two potentials allows tunable control of electronic, magnetic and optical properties. These findings underscore a novel pathway for tailoring SQD responses through careful design of the geometry of confining potential, offering promising applications in advanced optoelectronic and quantum information devices.