Enhancement of the g-factor and spin-density wave state in a confined 2DEG in the quantum Hall regime

We investigate the spin splitting of the Landau bands (LB's) in a confined two-dimensional electron gas (2DEG) using the Hartree-Fock approximation (HFA) for the mutual Coulomb interaction of the electrons. The exchange term of the interaction causes a large splitting of the spin levels of a LB whenever the chemical potential lies between them. These oscillations of the splitting with the filling factor of the LB's are conveniently interpreted as an oscillating enhancement of the effective g -factor, g *. The reduction of g * when a LB is becoming completely filled is accompanied by a spontaneous formation of a static spin-density wave state whose details depend on the system size and temperature.