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HL: Fachverband Halbleiterphysik

HL 31: Poster I: Devices, Quantum Dots and Quantum Wires

HL 31.28: Poster

Dienstag, 23. März 2010, 18:30–20:30, Poster D1

Noise measurements of a quantized charge pump — •Lukas Fricke¹, Niels Maire¹, Frank Hohls¹, Bernd Kästner², Christoph Leicht², Philipp Mirovsky², Hans Werner Schumacher², and Rolf J. Haug¹ — ¹Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, 30167 Hannover — ²Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig

Delivering a quantized number of electrons per cycle in a reliable fashion and at high repetition rate could satisfy the need for a current-quantum standard. A promising candidate is the non-adiabatic electron pump in semiconductor nanostructures, especially considering parallelization of these devices for higher current outputs.

We performed low frequency (f_n<10 kHz) current-noise measurements [1] of such a device at a pumping frequency of f_p=600 MHz. We observe a strong suppression of the noise power when the current is quantized in good agreement with a prediction for an ideal pump whereas in the intermediate region between two quantization plateaus an enhanced noise power can be measured. With these measurements different pumping processes can be distinguished.

[1] N.Maire et al., Appl. Phys. Lett. 92, 082112 (2008)