Place: Kleiner Physik-Hörsaal, Geschwister-Scholl-Platz
Date: 24.04.09, Time: 15:30 h
Hybrid single-electron transistor as a source of quantized electric current
Low Temperature Laboratory, Helsinki University of Technology, Finland
First I introduce the principles of single-electron current pumps and the various realizations conceived and tested. I briefly discuss the need of such a device in quantum metrology. The main topic of my talk is the hybrid normal-metal-superconductor turnstile in the form of a one-island single-electron transistor with one gate. The device demonstrates robust current plateaus at multiple levels of ef at frequency f. I discuss the various error mechanisms, based on our experiments and theoretical considerations. Ultimately the quantization accuracy is expected to be limited by either two-electron tunneling or by Cooper-pair–electron co-tunneling, and we predict that it should be possible to achieve the metrological accuracy of 10-8, while maintaining the quantized current on the level of more than 10 pA, just by one turnstile with realistic parameters using aluminum as a superconductor.
Collaborators: S. Kafanov, A. Kemppinen, V. Maisi, M. Meschke, M. Möttönen, J.J. Vartiainen, Yu.A. Pashkin, J.S. Tsai, O.-P. Saira, D.V. Averin
J.P. Pekola, J.J. Vartiainen, M. Möttönen, O.-P. Saira, M. Meschke, and D.V. Averin:
Nature Physics 4, 120 (2008).
A. Kemppinen, M. Meschke, M. Möttönen, D.V. Averin, and J.P. Pekola:
D.V. Averin and J.P. Pekola:
Phys. Rev. Lett. 101, 066801 (2008).
A. Kemppinen, S. Kafanov, Yu. A. Pashkin, J. S. Tsai, D. V. Averin, J. P. Pekola: