Physikalisch-Technische Bundesanstalt

"Scattering and Disorder in ultra-high mobility Two Dimensional Electron Systems"

Kolloquium der Abteilung 2

The experimental progress in quantum Hall physics over the last several decades was possible only due to the continuous improvement in the low temperature mobility of two-dimensional electron gas (2DEG), embedded in the GaAs-AlGaAs heterostructures grown by MBE.  We report the achievement of extremely high electron mobility of >20 × 10⁶ cm²/V·s in single interface 2DEG and 36 × 10⁶ cm²/V·s in 2DEG in Quantum Well.  All measurements were conducted at T=0.36 K in the dark. Surprisingly the quality of Fractional Quantum Hall Effect (FQHE) was not directly related to the mobility values, but was strongly influenced by introduction of correlations in the donor layer using precise doping.

---