Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Current measurement by real-time counting of single electrons

Nature volume 434, pages 361–364 (2005)Cite this article

Abstract

The fact that electrical current is carried by individual charges has been known for over 100 years, yet this discreteness has not been directly observed so far. Almost all current measurements involve measuring the voltage drop across a resistor, using Ohm's law, in which the discrete nature of charge does not come into play. However, by sending a direct current through a microelectronic circuit with a chain of islands connected by small tunnel junctions, the individual electrons can be observed one by one. The quantum mechanical tunnelling of single charges in this one-dimensional array is time correlated1,2,3, and consequently the detected signal has the average frequency f = I/e, where I is the current and e is the electron charge. Here we report a direct observation of these time-correlated single-electron tunnelling oscillations, and show electron counting in the range 5 fA–1 pA. This represents a fundamentally new way to measure extremely small currents, without offset or drift. Moreover, our current measurement, which is based on electron counting, is self-calibrated, as the measured frequency is related to the current only by a natural constant.

This is a preview of subscription content, access via your institution

Relevant articles

Open Access articles citing this article.

Access options

Rent or buy this article

Prices vary by article type

from$1.95

to$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Experimental set-up.
Figure 2: Array current–voltage characteristics in the superconducting state (S: B‖ = 475 mT, solid line) and in the normal state (N: 1.50 T, dashed line).
Figure 3: Experimental data.
Figure 4: Single-electron tunnelling oscillations.

References

  1. Ben-Jacob, E. & Gefen, Y. New quantum oscillations in current driven small junctions. Phys. Lett. A 108, 289–292 (1985)

    Article  ADS  Google Scholar 

  2. Averin, D. V. & Likharev, K. K. Coulomb blockade of single-electron tunneling, and coherent oscillations in small tunnel junctions. J. Low Temp. Phys. 62, 345–373 (1986)

    Article  ADS  Google Scholar 

  3. Likharev, K. K., Bakhvalov, N. S., Kazacha, G. S. & Serdyukova, S. I. Single electron tunnel junction array: An electrostatic analog of the Josephson transmission line. IEEE Trans. Magn. 25, 1436–1439 (1989)

    Article  ADS  Google Scholar 

  4. Averin, D. V., Zorin, A. B. & Likharev, K. K. Bloch oscillations in small Josephson junctions. Sov. Phys. JETP 61, 407–413 (1985)

    Google Scholar 

  5. Likharev, K. K. & Zorin, A. B. Theory of the Bloch-wave oscillations in small Josephson junctions. J. Low Temp. Phys. 59, 347–382 (1985)

    Article  ADS  Google Scholar 

  6. Delsing, P., Likharev, K. K., Kuzmin, L. S. & Claeson, T. Time correlated single electron tunneling in one-dimensional arrays of ultrasmall tunnel junctions. Phys. Rev. Lett. 63, 1861–1864 (1989)

    Article  ADS  CAS  Google Scholar 

  7. Geerligs, L. J. et al. Frequency-locked turnstile device for single electrons. Phys. Rev. Lett. 64, 2691–2694 (1990)

    Article  ADS  CAS  Google Scholar 

  8. Pothier, H., Lafarge, P., Urbina, C., Estève, D. & Devoret, M. H. Single-electron pump based on charging effects. Europhys. Lett. 17, 249–254 (1992)

    Article  ADS  Google Scholar 

  9. Keller, M. W., Martinis, J. M., Zimmerman, N. M. & Steinbach, A. H. Accuracy of electron counting using a 7-junction electron pump. Appl. Phys. Lett. 69, 1804–1806 (1996)

    Article  ADS  CAS  Google Scholar 

  10. Likharev, K. K. in Granular Nanoelectronics (eds Ferry, D., Barker, J. R. & Jacoboni, C.) 371–391 (Plenum, New York, 1991)

    Book  Google Scholar 

  11. Flensberg, K., Odintsov, A. A., Liefrink, F. & Teunissen, P. Towards single-electron metrology. Int. J. Mod. Phys. B 13, 2651–2687 (1999)

    Article  ADS  Google Scholar 

  12. Visscher, E. H. et al. Broadband single-electron tunneling transistor. Appl. Phys. Lett. 68, 2014–2016 (1996)

    Article  ADS  CAS  Google Scholar 

  13. Visscher, E. Technology and Applications of Single-Electron Tunneling Devices. Ph.D thesis, Delft Univ. Technol. (1996)

    Google Scholar 

  14. Lu, W., Ji, Z. Q., Pfeiffer, L., West, K. W. & Rimberg, A. J. Real-time detection of electron tunnelling in a quantum dot. Nature 423, 422–425 (2003)

    Article  ADS  CAS  Google Scholar 

  15. Fujisawa, T., Hayashi, T., Hirayama, Y., Cheong, H. D. & Jeong, Y. H. Electron counting of single-electron tunneling current. Appl. Phys. Lett. 84, 2343–2345 (2004)

    Article  ADS  CAS  Google Scholar 

  16. Blanter, Ya. M. & Büttiker, M. Shot noise in mesoscopic conductors. Phys. Rep. 336, 1–166 (2000)

    Article  ADS  CAS  Google Scholar 

  17. Cleland, A. N., Schmidt, J. M. & Clarke, J. Charge fluctuations in small-capacitance junctions. Phys. Rev. Lett. 64, 1565–1568 (1990)

    Article  ADS  CAS  Google Scholar 

  18. Kuzmin, L. S., Nazarov, Yu. V., Haviland, D. B., Delsing, P. & Claeson, T. Coulomb blockade and incoherent tunneling of Cooper pairs in ultrasmall junctions affected by strong quantum fluctuations. Phys. Rev. Lett. 67, 1161–1164 (1991)

    Article  ADS  CAS  Google Scholar 

  19. Delsing, P., Likharev, K. K., Kuzmin, L. S. & Claeson, T. Effect of high-frequency electrodynamic environment on the single-electron tunneling in ultrasmall junctions. Phys. Rev. Lett. 63, 1180–1183 (1989)

    Article  ADS  CAS  Google Scholar 

  20. Korotkov, A. N. Analytical calculation of single-electron oscillations in one-dimensional arrays of tunnel junctions. Phys. Rev. B 50, 17674–17677 (1994)

    Article  ADS  CAS  Google Scholar 

  21. Likharev, K. K. Single-electron transistors: Electrostatic analogs of the dc-squids. IEEE Trans. Magn. 23, 1142–1145 (1987)

    Article  ADS  Google Scholar 

  22. Fulton, T. A. & Dolan, G. J. Observation of single-electron charging effects in small tunnel junctions. Phys. Rev. Lett. 59, 109–112 (1987)

    Article  ADS  CAS  Google Scholar 

  23. Schoelkopf, R. J., Wahlgren, P., Kozhevnikov, A. A., Delsing, P. & Prober, D. E. The radio-frequency single-electron transistor (RF-SET): A fast and ultrasensitive electrometer. Science 280, 1238–1242 (1998)

    Article  ADS  CAS  Google Scholar 

  24. Pashkin, Y. A., Nakamura, Y. & Tsai, J. S. Metallic resistively coupled single-electron transistor. Appl. Phys. Lett. 74, 132–134 (1999)

    Article  ADS  CAS  Google Scholar 

  25. Korotkov, A. N. Theoretical analysis of the resistively coupled single-electron transistor. Appl. Phys. Lett. 72, 3226–3228 (1998)

    Article  ADS  CAS  Google Scholar 

  26. Delsing, P., Claeson, T., Kazacha, G. S., Kuzmin, L. S. & Likharev, K. K. 1-D array implementation of the resistively-coupled single-electron transistor. IEEE Trans. Magn. 27, 2581–2584 (1991)

    Article  ADS  Google Scholar 

  27. Bakhvalov, N. S., Kazacha, G. S., Likharev, K. K. & Serdyukova, S. I. Single-electron solitons in one-dimensional tunnel structures. Sov. Phys. JETP 68, 581–587 (1989)

    Google Scholar 

  28. Dolan, G. J. Offset masks for lift-off photoprocessing. Appl. Phys. Lett. 31, 337–339 (1977)

    Article  ADS  Google Scholar 

  29. Levitov, L. S., Lee, H. & Lesovik, G. B. Electron counting statistics and coherent states of electric current. J. Math. Phys. 37, 4845–4866 (1996)

    Article  ADS  MathSciNet  MATH  Google Scholar 

  30. Middleton, A. A. & Wingreen, N. S. Collective transport in arrays of small metallic dots. Phys. Rev. Lett. 71, 3198–3201 (1993)

    Article  ADS  CAS  Google Scholar 

  31. Kaplan, D. M., Sverdlov, V. A. & Likharev, K. K. Coulomb gap, Coulomb blockade, and dynamic activation energy in frustrated single-electron arrays. Phys. Rev. B 68, 45321 (2003)

    Article  ADS  Google Scholar 

Download references

Acknowledgements

We thank C. Kristoffersson, S. Pedersen and P. Wahlgren for assistance in the early stages of this work, K. Bladh, D. Gunnarsson, S. Kafanov and M. Taslakov for technical assistance, and T. Claeson, H. Nilsson, K-E. Rydler, G. Wendin, C. Wilson and A. Zorin for discussions. The work was supported by the Swedish SSF and VR, by the EU research project COUNT and by the Wallenberg foundation.

Author information

Authors and Affiliations

  1. Department of Microtechnology and Nanoscience (MC2), Chalmers University of Technology, SE-412 96, Göteborg, Sweden

    Jonas Bylander, Tim Duty & Per Delsing

Authors
  1. Jonas Bylander
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Tim Duty
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Per Delsing
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Jonas Bylander.

Ethics declarations

Competing interests

The authors declare that they have no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Bylander, J., Duty, T. & Delsing, P. Current measurement by real-time counting of single electrons. Nature 434, 361–364 (2005). https://doi.org/10.1038/nature03375

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nature03375

This article is cited by

Comments

By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing