Regensburg 2019 – wissenschaftliches Programm
HL 8.3: Vortrag
Montag, 1. April 2019, 15:30–15:45, H33
Magnetotunneling Spectroscopy of Imbalanced Double Quantum Wells — •Gunnar Lasse Schneider1, Werner Dietsche2, and Rolf J. Haug1 — 1Institut für Festkörperphysik, Leibniz Uni Hannover, Deutschland — 2MPI for Solid State Research, Stuttgart, Germany
Since several years bilayer phenomena such as 2D-2D Tunneling , Coulomb drag  and excitonic Bose-Einstein condensates (BEC)  are observable within double quantum wells in the Quantum Hall regime. Most studies were focused on balanced systems (i.e. the BEC was first found to arise at balanced layer densities with the filling factor combination of 1/2 and 1/2). In our work we are investigating imbalanced layers, allowing a mapping of the magnetotunneling characteristics at various filling factor combinations and the evolution of the excitonic condensate in the charge carrier density space.
All measurements were performed on a MBE grown GaAs double quantum well separated by a 10 nm AlAs/GaAs barrier. Each layer is individually contacted using field gates for a local depletion . Additional gates allow tuning the charge carrier densities between 1E10 and 4E10 per square centimeter. Our measurements show Quantum Hall selection rules in the magnetotunneling characteristics (Quantum Hall spin diode) and the transition towards excitonic condensation.
N. Turner et al., Phys. Rev. B 54, 10614 (1996)
C. Jörger et al., Physica E 6, 586 (2000)
J.P. Eisenstein and A.H. MacDonald, Nature 432, 691 (2004)
J.P. Eisenstein et al., Appl. Phys. Lett. 57, 2324 (1990)