Electron spin and donor impurity effects on the absorption spectra of pseudo-elliptic quantum rings under magnetic field

摘要

We investigated comparatively the electronic and optical properties of GaAs/GaAlAs pseudo-elliptic quantum rings with donor impurity under magnetic field in the absence and the presence of electron spin, taken into account through Rashba and Dresselhaus spin-orbit couplings and Zeeman effect. The energy and absorption spectra were computed for four representative positions of the donor impurity (edges and x(y)-middle of the ring). Both approaches demonstrate the important role played by the impurity position, with the strongest effects corresponding to the impurity placed in the middle of the ring. In the spin absence, the impurity position influences both the energies of the absorption peaks and their oscillatory behaviours in energy and amplitude. In the presence of electron spin, the absorption spectra of the pseudo-elliptic quantum ring become more complex at large magnetic fields as the number of transitions is increased by the splitting of the energy levels and present new distinct features at low and high energies that could be observed experimentally.