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HL: Fachverband Halbleiterphysik
HL 32: Transport Properties I (mainly Spin Physics and Magnetic Fields)
HL 32.1: Vortrag
Dienstag, 27. März 2012, 10:00–10:15, EW 203
A quantized 5/2 state in a two-subband electron system — •Johannes Nuebler1, Benedikt Frieß1, Vladimir Umansky2, Bernd Rosenow3, Moty Heiblum2, Klaus von Klitzing1, and Jurgen Smet1 — 1Max-Planck-Institut für Festkörperforschung, Stuttgart — 2Braun Centre for Semiconductor Research, Weizmann Institute of Science, Rehovot, Israel — 3Institute for Theoretical Physics, University of Leipzig
We investigate the fractional quantum Hall effect in wide quantum well heterostructures with tunable electron density. In contrast to previous measurements [1] we observe that upon population of the second subband the two subbands show independent quantum Hall states [2]. In particular, the fully quantized 5/2 state of the lower subband is surprisingly unaffected by the presence of the additional second subband electron system whose density we can vary over a wide range. We use tilted magnetic fields to modify the subband interaction.
[1] J. Shabani et al., Phys. Rev. Lett. 105, 246805 (2010).
[2] J. Nuebler et al., accepted for publication in PRL.