Letter | Published:

Kondo resonance in a single-molecule transistor



When an individual molecule1, nanocrystal2,3,4, nanotube5,6 or lithographically defined quantum dot7 is attached to metallic electrodes via tunnel barriers, electron transport is dominated by single-electron charging and energy-level quantization8. As the coupling to the electrodes increases, higher-order tunnelling and correlated electron motion give rise to new phenomena9,10,11,12,13,14,15,16,17,18,19, including the Kondo resonance10,11,12,13,14,15,16. To date, all of the studies of Kondo phenomena in quantum dots have been performed on systems where precise control over the spin degrees of freedom is difficult. Molecules incorporating transition-metal atoms provide powerful new systems in this regard, because the spin and orbital degrees of freedom can be controlled through well-defined chemistry20,21. Here we report the observation of the Kondo effect in single-molecule transistors, where an individual divanadium molecule20 serves as a spin impurity. We find that the Kondo resonance can be tuned reversibly using the gate voltage to alter the charge and spin state of the molecule. The resonance persists at temperatures up to 30 K and when the energy separation between the molecular state and the Fermi level of the metal exceeds 100 meV.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.


  1. 1

    Park, H. et al. Nano-mechanical oscillations in a single-C60 transistor. Nature 407, 57–60 (2000)

  2. 2

    Klein, D. L. et al. A single-electron transistor made from a cadmium selenide nanocrystal. Nature 389, 699–701 (1997)

  3. 3

    Park, H. et al. Fabrication of metallic electrodes with nanometer separation by electromigration. Appl. Phys. Lett. 75, 301–303 (1999)

  4. 4

    Banin, U., Cao, Y., Katz, D. & Millo, O. Identification of atomic-like electronic states in indium arsenide nanocrystal quantum dots. Nature 400, 542–544 (1999)

  5. 5

    Tans, S. J. et al. Individual single-wall carbon nanotubes as quantum wires. Nature 386, 474–476 (1997)

  6. 6

    Bockrath, M. et al. Single-electron transport in ropes of carbon nanotubes. Science 275, 1922–1925 (1997)

  7. 7

    Kouwenhoven, L. P. et al. Excitation spectra of circular few-electron quantum dots. Science 278, 1788–1792 (1997)

  8. 8

    Grabert, H. & Devoret, M. H. Single Charge Tunneling (Plenum, New York, 1992)

  9. 9

    Liang, W. et al. Fabry-Perot interference in a nanotube electron waveguide. Nature 411, 665–669 (2001)

  10. 10

    Goldhaber-Gordon, D. et al. Kondo effect in a single-electron transistor. Nature 391, 156–159 (1998)

  11. 11

    Cronenwett, S. M., Oosterkamp, T. H. & Kouwenhoven, L. P. A tunable Kondo effect in quantum dots. Science 281, 540–544 (1998)

  12. 12

    Goldhaber-Gordon, D. et al. From the Kondo regime to the mixed-valence regime in a single-electron transistor. Phys. Rev. Lett. 81, 5225–5228 (1998)

  13. 13

    Schmid, J., Weis, J., Eberl, K. & Klitzing, K. v. Absence of odd-even parity behaviour for Kondo resonances in quantum dots. Phys. Rev. Lett. 84, 5824–5827 (2000)

  14. 14

    van der Wiel, W. G. et al. The Kondo effect in the unitary limit. Science 289, 2105–2108 (2000)

  15. 15

    Nygard, J., Cobden, D. H. & Lindelof, P. E. Kondo physics in carbon nanotubes. Nature 408, 342–346 (2000)

  16. 16

    Liang, W., Bockrath, M. & Park, H. Shell filling and exchange coupling in metallic single-walled carbon nanotubes. Phys. Rev. Lett. 88, 126801-1–126801-4 (2002)

  17. 17

    Glazman, L. I. & Raikh, M. E. Resonant Kondo transparency of a barrier with quasilocal impurity states. JETP Lett. 47, 452–455 (1988)

  18. 18

    Ng, T. K. & Lee, P. A. On-site Coulomb repulsion and resonant tunneling. Phys. Rev. Lett. 61, 1768–1771 (1988)

  19. 19

    Meir, Y., Wingreen, N. S. & Lee, P. A. Low-temperature transport through a quantum dot: The Anderson model out of equilibrium. Phys. Rev. Lett. 70, 2601–2604 (1993)

  20. 20

    Shores, M. P. & Long, J. R. Tetracyanide-bridged divanadium complexes: Redox switching between strong antiferromagnetic and strong ferromagnetic coupling. J. Am. Chem. Soc. 124, 3512–3513 (2002)

  21. 21

    Shores, M. P., Sokol, J. J. & Long, J. R. Nickel(II)-molybdenum(III)-cyanide clusters: Synthesis and magnetic behaviour of species incorporating [(Me3tacn}Mo(CN)3]. J. Am. Chem. Soc. 124, 2279–2292 (2002)

  22. 22

    Bachtold, A., Hadley, P., Nakanishi, T. & Dekker, C. Logic circuits with carbon nanotube transistors. Science 294, 1317–1320 (2001)

  23. 23

    Schlottmann, P. Some exact results for dilute mixed-valent and heavy-fermion systems. Phys. Rep. 181, 1–119 (1989)

  24. 24

    Hewson, A. C. The Kondo Problem to Heavy Fermions (Cambridge Univ. Press, Cambridge, 1993)

  25. 25

    Cobden, D. H. et al. Spin splitting and even-odd effects in carbon nanotubes. Phys. Rev. Lett. 81, 681–684 (1998)

  26. 26

    Haldane, F. D. M. Scaling theory of the asymmetric Anderson model. Phys. Rev. Lett., 416–419 (1978)

  27. 27

    Wingreen, N. S. & Meir, Y. Anderson model out of equilibrium: Noncrossing-approximation approach to transport through a quantum dot. Phys. Rev. B 49, 11040–11052 (1994)

  28. 28

    Lin, H. Q. & Hirsch, J. E. Magnetic properties of a degenerate Anderson impurity. Phys. Rev. B 37, 1864–1873 (1988)

  29. 29

    Bonca, J. & Gubernatis, J. E. Quantum Monte Carlo simulations of the degenerate single-impurity Anderson model. Phys. Rev. B 47, 13137–13146 (1993)

  30. 30

    De Franceschi, S. et al. Electron cotunneling in a semiconductor quantum dot. Phys. Rev. Lett. 86, 878–881 (2001)

Download references


We thank C. Lieber, B. Halperin and D. R. Reichman for discussions. This work was supported by NSF, DARPA, the Dreyfus Foundation, the Packard Foundation, the Research Corporation, and Harvard University (H.P.) and NSF (J.R.L.). M.B. is partially supported by the Department of Physics, Harvard University.

Author information

Competing interests

The authors declare that they have no competing financial interests.

Correspondence to Hongkun Park.

Rights and permissions

To obtain permission to re-use content from this article visit RightsLink.

About this article

Further reading

Figure 1: Fabrication of single-molecule transistors incorporating individual divanadium molecules.
Figure 2: Plots of differential conductance (∂I/∂V) as a function of bias voltage (V) and gate voltage (Vg) obtained from two different single-V2 transistors D1 (a) and D2 (b).
Figure 3: Transport data obtained from single-V2 transistors in an applied magnetic field (B).
Figure 4: Temperature-dependent transport data from device D3.


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.