Dresden 2003 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 49: Poster II
HL 49.39: Poster
Donnerstag, 27. März 2003, 16:30–19:00, HSZ/P2
The Enhanced g-factor in a Quantum Wire — •Siawoosh Mohammadi1, Alexander Struck1, S. Ketteman1, B. Kramer1, and T. Brandes2 — 1I. Institute ofTheoretical Physics, University of Hamburg,Germany — 2Department of Physics, University of Manchester
We calculate the exchange enhanced Landé g-factor in the lowest Landau level in quantum wires subject to a strong homogeneous perpendicular magnetic field. Our calculations start from the model of Kinaret and Lee[1], in which the spin polarization is determined by the competition between exchange interaction and kinetic energy of the edge-channel electrons. We extend their approach by inclusion of the Hartree interaction in first order perturbation theory as well as by solving the self-consistent Hartree-Fock equations. The latter are mapped onto the spin-unrestricted Pople-Nesbet equations in order to resolve the spin-split Landau levels. We show that the critical electron density ρc, above which the total polarization breaks down, rises in the extended model, because the Hartree interaction, just as the exchange interaction, favors the full polarization. We find that this effect increases the g-factor at the critical density. The extended model and the original theory of Kinaret and Lee are compared to measurements by Pallecchi et al.[2], in which ρc is studied at varying strength of the confinement potential. With the aid of one fitting parameter the extended model accounts well, whereas the original theory fails about one order of magnitude.
[1] Jari M. Kinaret and Patrick A. Lee, Phys. Rev. B 42, 11768 (1990).
[2] I. Pallecchi et al. Phys. Rev. B 65, 125303.