Regensburg 2002 – wissenschaftliches Programm
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HL: Halbleiterphysik
HL 16: Transport im hohen Magnetfeld / QHE
HL 16.8: Vortrag
Dienstag, 12. März 2002, 12:45–13:00, H15
The fractional quantum Hall effect in 110-oriented GaAs quantum wells — •Frank Fischer, Matthew Grayson, Dieter Schuh, Max Bichler und Gerhard Abstreiter — Walter Schottky Institut, Technische Universitaet Muenchen, 85748 Garching
We optimize the mobility of two-dimensional electron systems (2DES) grown on 110-oriented GaAs crystals. Perpendicular to the standard 001-growth plane, the 110-plane is the natural cleave plane of GaAs relevant for cleaved-edge overgrowth. In order to study the fractional quantum Hall effect (FQHE), the 2DES are optimized for low density, n = 1 x 1011 cm−2. We vary the temperatures, pressures, and crystal growth rates and find an optimal mobility of µ 3 x 106 cm2/Vs, with the samples showing clear FQHE states at filling factor ν=1/3, 2/3, 3/5, 2/5, 4/7, 3/7, 4/9 and 5/9 at a measurement temperature of 300 mK. The electrical characterization and surface morphology of samples grown on 110 substrates are compared to samples grown on both cleaved and pre-cleaved 110 surfaces.