Berlin 2005 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 53: Transport im hohen Magnetfeld/Quanten-Hall-Effekt
HL 53.1: Vortrag
Dienstag, 8. März 2005, 15:00–15:15, TU P270
Edge states at corner junctions of two orthogonal quantum Hall systems — •Lucia Steinke and Matthew Grayson — Walter Schottky Institut, TU München, D-85748 Garching, Germany
Recently Grayson et al. [1] succeeded in fabricating a new kind of GaAs/AlGaAs heterostructure with a high-mobility two-dimensional electron system bent at an atomically sharp 90∘ angle.
When a quantizing magnetic field is applied to the structure with a tilt angle θ, the system represents a corner junction of two orthogonal quantum Hall systems with filling factor ratio ν1/ν2=n1/n2tanθ,
where n1 and n2 are the 2D electron densities on the respective facets.
The bandstructure of this novel quantum Hall line junction in a tilted magnetic field was calculated in the Hartree approximation, revealing a non-trivial corner dispersion.
Based on the calculated results for the edge channel spectrum, the corner state could be interpreted as a hybrid system of quantum Hall edges with a bound wire state at the corner.
Repeated calculations at various tilted magnetic fields allowed predictions about the conductance properties of the corner states, yielding qualitative explanations for the experimental results presented in Ref. [1].
[1] M. Grayson, D. Schuh, M. Huber, M. Bichler, and G. Abstreiter, APL, to be published; M. Grayson, D. Schuh, M. Bichler, M. Huber, G. Abstreiter, L. Hoeppel, J. Smet, and K. von Klitzing, Physica E 22, 181 (2004)