Regensburg 2016 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 47: Quantum Hall Effect
HL 47.2: Vortrag
Mittwoch, 9. März 2016, 09:45–10:00, H14
Terahertz induced oscillations of magnetoresistivity in AlGaAs/GaAs quantumwells (QW) — •Tobias Herrmann1, Ze Dong Kvon2, Dmitriy A. Kozlov2, Vasily V. Bel’kov3, Bruno Jentzsch1, Martin Schneider1, Peter Olbrich1, Dominique Bougeard1, Dieter Weiss1, and Sergey D. Ganichev1 — 1University of Regensburg, Regensburg, Germany — 2Institute of Semiconductor Physics, Novosibirsk, Russia — 3Ioffe Institute, St. Petersburg, Russia
We report on the observation of MIRO-like oscillations (Microwave Induced Resistivity Oscillations) in GaAs-based two dimensional electron systems (2DES). The 1/B periodic oscillations are detected in corbino disk very low and high mobility QW samples excited by radiation with f = 0.69 THz. Strikingly we observe that the oscillations* amplitudes, in contrast to cyclotron resonance (CR), only slightly depend on the radiation helicity, even in the vicinity of CR. This result is insofar important that existing theories predict the amplitude of MIRO to depend on the helicity of the circular polarization via the factor 1/[(ω ± ωc)2 + 1/τ2], where the minus (plus) sign corresponds to active (inactive) polarization[1]. Furthermore, scanning the beam across the sample with the beam size smaller than the corbino disc diameter we observed that the oscillations are excited in the 2DES and not at the structure edges. This observation demonstrates that edge effects caused by pondermotive forces[2] are not responsible for the observed MIRO-like oscillations. [1] Dmitriev et al., Rev. Mod. Phys., 84. 1709 (2012) [2] Mikhailov, Phys. Rev. B, 89, 045410 (2014)