Regensburg 2002 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

HL: Halbleiterphysik

HL 11: Poster 1

HL 11.45: Poster

Montag, 11. März 2002, 17:00–19:30, Poster A

Quantum Hall effect in very large samples — •Dorina Diaconescu, Andreas Goldschmidt, Dirk Reuter, and Andreas D. Wieck — Ruhr-Universität Bochum, D44780 Bochum, Germany

Magnetotransport measurements in the Quantum Hall regime have been performed on Hall bars with an overall length of up to 90 cm defined from Al_xGa_1−xAs/GaAs heterostructures containing a high quality two dimensional electron gas (2DEG). We observe the same magnetoresistance variations as for samples on the micrometer scale but the height of the maxima does not scale with the length of the Hall bar as expected from simple theory. For very long samples, the amplitude of the maxima becomes independent on the magnetic field, because of the enhanced scattering between the edge states. To clarify the role of the disorder we change the disorder in the sample by low dose ion implantation. This allows the modification of the electron mobility, i. e. the degree of disorder, without changing the electron density.