Spin–Orbit and Zeeman Effects on the Electronic Properties of Single Quantum Rings: Applied Magnetic Field and Topological Defects
Abstract
Within the framework of effective mass theory, we investigate the effects of spin–orbit
interaction (SOI) and Zeeman splitting on the electronic properties of an electron confined in GaAs
single quantum rings. Energies and envelope wavefunctions in the system are determined by solving
the Schrödinger equation via the finite element method. First, we consider an inversely quadratic
model potential to describe electron confining profiles in a single quantum ring. The study also
analyzes the influence of applied electric and magnetic fields. Solutions for eigenstates are then used
to evaluate the linear inter-state light absorption coefficient through the corresponding resonant
transition energies and electric dipole matrix moment elements, assuming circular polarization for
the incident radiation. Results show that both SOI effects and Zeeman splitting reduce the absorption
intensity for the considered transitions compared to the case when these interactions are absent.
In addition, the magnitude and position of the resonant peaks have non-monotonic behavior with
external magnetic fields. Secondly, we investigate the electronic and optical properties of the electron
confined in the quantum ring with a topological defect in the structure; the results show that the
crossings in the energy curves as a function of the magnetic field are eliminated, and, therefore,
an improvement in transition energies occurs. In addition, the dipole matrix moments present a
non-oscillatory behavior compared to the case when a topological defect is not considered.