Dresden 2017 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 77: Transport in High Magnetic Fields
HL 77.4: Vortrag
Donnerstag, 23. März 2017, 15:45–16:00, POT 112
Interlayer magnetotransport phenomena of double quantum wells — •Gunnar L. Schneider1, Rolf J. Haug1, and Werner Dietsche2 — 1Institut für Festkörperphysik, Leibniz Universität Hannover, Germany — 2Max Planck Institut für Festkörperphysik, Stuttgart, Germany
We study the transport phenomena of two parallel 2-dimensional electron systems in a magnetic field, especially at the v_T=1 state of excitonic condensation. These systems are realized by a GaAs/AlGaAs double quantum well separated by an AlAs isolation layer and defined by the ratio of the layer-to-layer distance d to the magnetic length l_B. Hallbar geometry in combination with selective field gating allow an independent characterization of each layer's magnetotransport properties, investigating the interlayer electron-electron Coulomb interaction and measuring the magneto dependent interlayer I/V tunnel current [1].
The existence of a BEC excitonic state was raised over 40 years ago and our used sample geometry has been proven to contain such a condensate [2]. Our measurements show evidences that we are able to create a BEC excitonic state and the signals correlate to the d/l_B -value. In addition we performed highly resolved magneto dependent I/V tunnel characteristics from zero up to two Tesla at which we see the v_T=1 BEC excitonic state and an underlying pattern due to the Coulomb interaction between the layers and quantum Hall physics.
[1] L. Tiemann et al., New J. of Phys. 10, 045018 (2008)
[2] J. P. Eisenstein and A. H. MacDonald, Nature 432, 691 (2004)