PICO

Single-Electron Turnstile

Highlights of recent research:

Reaching metrological accuracy with the SINIS single-electron turnstile [pdf]

Andreev tunneling in NIS junctions and SINIS turnstiles [pdf]

The synchronous manipulation of individual electrons in solid-state devices became available when single electronics started about two decades ago. Ultrasmall structures in a low-temperature environment form an ideal domain for addressing electrons one by one. In the so-called metrological triangle, voltage from the Josephson effect and resistance from the quantum Hall effect would be tested against current via Ohm's law for a consistency check of the fundamental constants of nature, h and e. Several attempts to create a metrological current source that would comply with the demanding criteria of extreme accuracy, high yield and implementation with not too many control parameters have been reported. We have proposed and proven the concept of a hybrid normal-metal–superconductor turnstile in the form of a one-island single-electron transistor with one gate, which demonstrates robust current plateaux at multiple levels of ef at frequency f. Theoretically the quantization accuracy is limited by the trade-off between the processes of missed electron tunneling, backward tunneling, Andreev reflection and Cooper-pair–electron cotunneling.

It should be possible to achieve the metrological accuracy of 10-8, while maintaining the quantized current of few tens of pA, just by one turnstile with realistic parameters using aluminum as a superconductor. In 2008 work focused on identifying the various error sources in this pumping scheme.

Fig 1: Current plateaus at I = nef of a hybrid single-electron turnstile measured at f = 20 MHz.

Group meetings

Where? Grünberg, Micronova
When? Every Monday @9am
Each time we have an informal talk.

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Contact Information

PICO-group
Low Temperature Laboratory,
Department of Applied Physics,
Aalto University School of Science

Visiting address:
Micronova, Tietotie 3, Espoo, Finland
Postal address:
P.O. Box 13500, FIN-00076 AALTO, Finland

Fax: +358-9-470 25008

Tel: +358 40 700 9290,
+358 50 344 2697
e-mail: jukka.pekola(at)aalto.fi
web: http://ltl.tkk.fi/PICO

Our measurement laboratory and offices in the Micronova building are placed on the fourth floor, in rooms 4142 (lab) and 4110 - 4112, 4140, 4160 (offices).

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