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HL: Halbleiterphysik
HL 57: Theory of electronic structure
HL 57.1: Vortrag
Freitag, 31. März 2006, 11:00–11:15, BEY 118
Magnetic band structure of GaAs and InSb in ultrahigh magnetic fields — •Christian Ammann, Christian Strahberger, and Peter Vogl — Walter Schottky Institut, Technische Universität München, D-85748 Garching, Germany
The availability of ultrahigh magnetic fields for solid state investigations calls for reliable theoretical predictions of the electronic band structure in ultrahigh fields. We have calculated the magnetic band structure and optical absorption spectra of bulk GaAs and bulk InSb by means of an empirical sp3d5s∗ tight binding model where the magnetic field is incorporated non-perturbatively to capture effects that can only arise by taking the entire Brillioun zone into account. In fields up to 1000 T, the band structure can be interpreted in terms of Landau ladders arising from all valleys throughout the BZ whereas the spectrum shows a fractal behavior for higher fields. There is a strong dependence of the magnetic band structure on the B-field direction because of zone folding effects. We find the lowest L↓ -band state to cross the lowest Γ ↑ -band state in GaAs at 600 T. The effective Lande g factor in InSb shows a strongly sublinear behavior due to strong hybridization of Γ and L band states beyond 100 T. For GaAs as well as InSb, we find efficient optical absorption in the far infrared range for intra-valence band transitions for B-fields between 100 T and 500 T.