Berlin 2015 – scientific programme

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HL: Fachverband Halbleiterphysik

HL 60: Quantum dots: Transport

HL 60.6: Talk

Wednesday, March 18, 2015, 18:30–18:45, EW 203

Electron Transport in a Quadruple Quantum Dot System — •Johannes Bayer, Timo Wagner, Eddy P. Rugeramigabo, and Rolf J. Haug — Institut für Festkörperphysik, Leibniz Universität Hannover

We successfully produced a tunable system of four tunnel-coupled quantum dots in series. The device was fabricated via electron beam lithography on an MBE-grown GaAs /AlGaAs heterostructure forming a 2DEG 110 nm beneath the surface with an electron density of 2.4 · 10¹¹  cm⁻² and an electron mobility of 5.1 · 10⁵  cm²/Vs. We performed electronic transport measurements in a dilution refrigerator at a base temperature of about 10 mK. The quadruple quantum dot system (QQD) has been studied in terms of linear and nonlinear transport behavior. Additionally, two quantum point contacts are located near the quantum dots and used as sensitive charge detectors. We present a combination of transport measurements and charging diagrams in the many electron regime of the QQD.