Field regulation of single-molecule conductivity by a charged surface atom


Electrical transport through molecules has been much studied since it was proposed1 that individual molecules might behave like basic electronic devices, and intriguing single-molecule electronic effects have been demonstrated2,3. But because transport properties are sensitive to structural variations on the atomic scale4,5,6,7, further progress calls for detailed knowledge of how the functional properties of molecules depend on structural features. The characterization of two-terminal structures has become increasingly robust and reproducible8,9,10,11,12, and for some systems detailed structural characterization of molecules on electrodes or insulators is available13,14,15,16,17. Here we present scanning tunnelling microscopy observations and classical electrostatic and quantum mechanical modelling results that show that the electrostatic field emanating from a fixed point charge regulates the conductivity of nearby substrate-bound molecules. We find that the onset of molecular conduction is shifted by changing the charge state of a silicon surface atom, or by varying the spatial relationship between the molecule and that charged centre. Because the shifting results in conductivity changes of substantial magnitude, these effects are easily observed at room temperature.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.


All prices are NET prices.

Figure 1: Visualization of the electrostatic potential emanating from a point source.
Figure 2: Absence of charge field effects on low-doped silicon.
Figure 3: Reversible modification of dangling bonds.
Figure 4: Orbitals and charge densities near a dangling bond.
Figure 5: Change in electronic properties with distance from the dangling bond.


  1. 1

    Aviram, A. & Ratner, M. A. Molecular rectifiers. Chem. Phys. Lett. 29, 277–283 (1974)

  2. 2

    Kubatkin, S. et al. Single-electron transistor of a single organic molecule with access to several redox states. Nature 425, 698–701 (2003)

  3. 3

    Park, J. et al. Coulomb blockade and the Kondo effect in single-atom transistors. Nature 417, 722–725 (2002)

  4. 4

    Kaun, C.-C., Guo, H., Grütter, P. & Lennox, R. B. Momentum filtering effect in molecular wires. Phys. Rev. B 70, 195309 (2004)

  5. 5

    Yang, Z., Chshiev, M., Zwolak, M. & Di Ventra, M. Role of heating and current-induced forces in the stability of atomic wires. Phys. Rev. B 71, 041402(R) (2005)

  6. 6

    Damle, P., Rakshit, T., Paulsson, M. & Datta, S. Current–voltage characteristics of molecular conductors: two versus three terminal. IEEE Trans. Nanotech. 1, 145–153 (2002)

  7. 7

    Emberly, E. G. & Kirczenow, G. The smallest molecular switch. Phys. Rev. Lett. 91, 188301 (2003)

  8. 8

    Reed, M. A., Zhou, C., Muller, C. J., Burgin, T. P. & Tour, J. M. Conductance of a molecular junction. Science 278, 252–254 (1997)

  9. 9

    Cui, X. D. et al. Reproducible measurement of single-molecule conductivity. Science 294, 571–574 (2001)

  10. 10

    Selzer, Y. et al. Effect of local environment on molecular conduction: Isolated molecule versus self-assembled monolayer. Nano Lett. 5, 61–65 (2005)

  11. 11

    Wold, D. J., Haag, R., Rampi, M. A. & Frisbee, C. D. Distance dependence of electron tunneling through self-assembled monolayers measured by conducting probe atomic force microscopy: Unsaturated versus saturated molecular junctions. J. Phys. Chem. B 106, 2813–2816 (2002)

  12. 12

    Joachim, C. & Gimzewski, J. K. An electrochemical amplifier using a single molecule. Chem. Phys. Lett. 265, 353–357 (1997)

  13. 13

    Nazin, G. V., Qiu, X. H. & Ho, W. Visualization and spectroscopy of a metal-molecule-metal bridge. Science 302, 77–81 (2003)

  14. 14

    Moresco, F. et al. Probing the different stages in contacting a single molecular wire. Phys. Rev. Lett. 91, 036601 (2003)

  15. 15

    Grill, L. et al. Controlled manipulation of a single molecular wire along a copper atomic nanostructure. Phys. Rev. B 69, 035416 (2004)

  16. 16

    Mayne, A. J. et al. Chemisorbed bistable molecule: Biphenyl on Si(100)-2x1. Phys. Rev. B 69, 045409 (2004)

  17. 17

    Repp, J., Meyer, G., Stojković, S. M., Gourdon, A. & Joachim, C. Molecules on insulating films: Scanning-tunneling microscopy imaging of individual molecular orbitals. Phys. Rev. Lett. 94, 026803 (2005)

  18. 18

    Lopinski, G. P., Wayner, D. D. M. & Wolkow, R. A. Self-directed growth of molecular nanostructures on silicon. Nature 406, 48–51 (2000)

  19. 19

    DiLabio, G. A., Piva, P. G., Kruse, P. & Wolkow, R. A. Dispersion interactions enable the self-directed growth of linear alkane nanostructures covalently bound to silicon. J. Am. Chem. Soc. 126, 16048–16050 (2004)

  20. 20

    Sze, S. M. Physics of Semiconductor Devices Ch. 1 (Wiley-Interscience, New York, 1981)

  21. 21

    Bardeen, J. Surface states and rectification at a metal-semiconductor interface. Phys. Rev. 71, 717–727 (1947)

  22. 22

    Feenstra, R. M., Meyer, G. & Rieder, K. H. Transport limitations in tunneling spectroscopy of Ge(111)c(2 × 8) surfaces. Phys. Rev. B 69, 081309(R) (2004)

  23. 23

    Pitters, J. L. & Wolkow, R. A. Protection-deprotection chemistry to control styrene self-directed line growth on hydrogen-terminated Si(100). J. Am. Chem. Soc. 127, 48–49 (2005)

  24. 24

    Dewar, M. J. S., Zoebisch, E. G., Healy, E. F. & Stewart, J. J. P AM1: A new general purpose quantum mechanical molecular model. J. Am. Chem. Soc. 107, 3902–3909 (1985)

  25. 25

    Boese, A. D. & Handy, N. C. A new parameterization of exchange-correlation generalized gradient approximation functionals. J. Chem. Phys. 114, 5497–5503 (2001)

  26. 26

    Stevens, W., Basch, H. & Krauss, J. Compact effective potentials and efficient shared-exponent basis sets for the first- and second-row atoms. J. Chem. Phys. 81, 6026–6033 (1984)

  27. 27

    Perdew, J. P., Burke, K. & Ernzerhof, M. Generalized gradient approximation made simple. Phys. Rev. Lett. 77, 3865–3868 (1996)

  28. 28

    Frisch, M. J., et al. Gaussian 03 Revision C.02 (Gaussian, Inc., Wallingford, Connecticut, 2004)

  29. 29

    Tersoff, J. & Hamann, D. R. Theory and application for the scanning tunneling microscope. Phys. Rev. Lett. 50, 1998–2001 (1983)

  30. 30

    Herzberg, G. Atomic Spectra and Atomic Structure 2nd edn, Ch. II, 114 (Dover, New York, 1944)

Download references


We have benefited from discussions with G. Kirczenow, G. Lopinski, S. Datta, H. Guo and R. Feenstra and from the technical expertise of M. Cloutier and D. Moffatt. Funding has been provided by iCORE, the NRC, the NSERC, CFI, the University of Alberta and CIAR. We are grateful for access to WestGrid and the Center of Excellence in Integrated Nanotools (University of Alberta) computational facilities.

Author information

Correspondence to Robert A. Wolkow.

Ethics declarations

Competing interests

Reprints and permissions information is available at The authors declare no competing financial interests.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Piva, P., DiLabio, G., Pitters, J. et al. Field regulation of single-molecule conductivity by a charged surface atom. Nature 435, 658–661 (2005).

Download citation

Further reading


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.