Spin Configuration of a Circular Quantum Dot in a Magnetic Field

Abstract

In this paper, we present an approach for modeling the spin configuration of a two-dimensional circular quantum dot in a magnetic field based on the interacting Green's functions on a tight-binding basis, where the electron-electron interaction is represented by the retarded self-energy. The quantum dot is composed of a circular lattice of tight-binding sites and has a cylindrically symmetric electrostatic confinement approximated by a harmonic potential. Using this approach, we were able to obtain the single electron energy spectrum and the spin state as a function of magnetic field up to the twentieth level. We found that the shell structure in energy spectrum appears not only at zero magnetic field but also at a specific moderate magnetic field. The fine structures of energy levels in the shell are well identified by evaluating the mean radius of eigenfunction. At a strong magnetic field, we found that complete spin polarization progresses from lower level to higher level with the magnetic field. The subsequent state transition and the fine structures in energy levels are made clear as a function of magnetic field.