Tuning electronic and magnetic properties of off-center D− impurity in GaAs quantum dots with spin–orbit interactions and magnetic field

Abstract

Our investigation into the electronic, magnetic, and correlation properties of an off-center negatively charged donor $\left(D^{-}\right)$ in a GaAs quantum dot with Gaussian confinement is a novel and intriguing area of research. Conducted under the influence of Rashba and Dresselhaus spin–orbit interactions and an external magnetic field, we have derived analytical expressions for ground-state energy, binding energy, dipole moment, and pair correlation function using the effective mass approximation and Ritz variational approach. The binding energy peaks when the impurity is centered and decreases with off-center displacement, potentially leading to an unbound state. Dresselhaus spin–orbit interaction enhances binding at the dot’s center, while Rashba spin–orbit interaction dominates with larger displacements, inducing charge asymmetry that impacts electronic and spintronic properties. Magnetic fields strengthen electron localization, potentially restoring binding in less favorable configurations. Impurity position and spin–orbit interactions significantly influence dipole moment and electron–electron correlation. Phase diagrams delineate parameter ranges for stable two-electron binding, offering novel insights into tunable donor-bound states for quantum device applications.