Berlin 2008 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 17: Poster I
HL 17.12: Poster
Montag, 25. Februar 2008, 16:30–19:00, Poster D
FIR and MW Spectroscopy on Carbon-Doped Two-Dimensional Hole Systems — •Kevin Rachor1, Thomas Raab1, Carsten Graf von Westarp1, Detlef Heitmann1, Andrea Stemmann1, Christian Heyn1, Christian Gerl2, Werner Wegscheider2, Dirk Reuter3, and Andreas Wieck3 — 1Institut für Angewandte Physik, Uni Hamburg, 20355 Hamburg — 2Institut für Experimentelle und Angewandte Physik, Uni Regensburg, 93040 Regensburg — 3Ruhr-Universität Bochum, 44801 Bochum
The recent development of Carbon-doped AlGaAs heterostructures on (100) substrates permits an experimental access to two-dimensional hole systems (2DHS) with high mobilities and no anisotropy [1]. Using a microwave generator and a Fourier transform spectrometer we perform both microwave and broadband far infrared transmission experiments on such samples covering a frequency range from 50 GHz to 20.000 GHz (1.67 cm−1 to 600 cm−1). Cyclotron resonances measured in perpendicular magnetic fields up to 14 T at 1.6 K are presented here. The effective mass m* shows a strong magnetic field dependance revealing the highly non-parabolic band structure of hole systems. Surprisingly, m* depends strongly on the temperature, too. In a certain regime of the magnetic field an additional resonance, propably an intersubband resonance is detected which is possible due to a warping of the energy contour [2]. The authors are grateful to the DFG for support through SFB 508.
[1] A. D. Wieck et al. Appl. Phys. Lett. 85, 2277 (2004).
[2] E. Bangert et al. PRL 53, 493 (1984).