Regensburg 2004 – scientific programme

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HL: Halbleiterphysik

HL 25: Heterostrukturen II

HL 25.2: Talk

Tuesday, March 9, 2004, 18:15–18:30, H14

Edge magneto plasmons in GaAs and GaN-based heterojunctions — •Hans Huebl, Thomas Vallaitis, Sebastian T. B. Goennenwein, and Martin S. Brandt — Walter Schottky Institut, Technische Universität München, München, Germany

Various processes can influence the microwave properties of low-dimensional electron systems, such as absorption caused by cyclotron resonance, spin resonance or quantum oscillations. However, also collective excitations such as plasmons can be excited in experimental set-ups used to study these processes. Since absorption by plasmons can be very strong, it can easily dominate the spectra observed. In this contribution, we report a detailed investigation of the absorption caused by edge magneto plasmons (EMPs) in two-dimensional electron gases (2DEG). EMPs in InGaAs quantum well structures as well as in GaN-AlGaN heterostructures have been studied, allowing a variation of the charge carrier density by more than one order of magnitude. Very good agreement with the theory of Allen et al.[1] is found, while the more elaborate theory of Volkov and Mikhailov[2] is not required to account for the experimental data. Therefore, 2DEG samples with circumferences of >1 cm or <50 µ m e.g. in checkerboard arrangement will be necessary to study spin effects.

[1] S. J. Allen, H. L. Störmer and J. C. M. Hwang, PRB28, 4875 (1983)

[2] V. Volkov and S. A. Mikhailov, Landau Level Spectroscopy, ed. by G. Landwehr and E. I. Rashba, Springer Verlag, Berlin, Chapter 15, p.855 (1991)