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Imaging the charge distribution within a single molecule

Abstract

Scanning tunnelling microscopy and atomic force microscopy can be used to study the electronic and structural properties of surfaces, as well as molecules and nanostructures adsorbed on surfaces, with atomic precision1,2,3,4,5,6,7, but they cannot directly probe the distribution of charge in these systems. However, another form of scanning probe microscopy, Kelvin probe force microscopy, can be used to measure the local contact potential difference between the scanning probe tip and the surface, a quantity that is closely related to the charge distribution on the surface8,9,10,11,12. Here, we use a combination of scanning tunnelling microscopy, atomic force microscopy and Kelvin probe force microscopy to examine naphthalocyanine molecules (which have been used as molecular switches13) on a thin insulating layer of NaCl on Cu(111). We show that Kelvin probe force microscopy can map the local contact potential difference of this system with submolecular resolution, and we use density functional theory calculations to verify that these maps reflect the intramolecular distribution of charge. This approach could help to provide fundamental insights into single-molecule switching and bond formation, processes that are usually accompanied by the redistribution of charge within or between molecules14,15,16.

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Figure 1: STM and AFM imaging of naphthalocyanine on NaCl(2 ML)/Cu(111).
Figure 2: LCPD images of the tautomerization switching of naphthalocyanine.
Figure 3: Enhanced resolution in LCPD images by tip functionalization with CO.

References

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

    Article  CAS  Google Scholar 

  2. Sugimoto, Y. et al. Chemical identification of individual surface atoms by atomic force microscopy. Nature 446, 64–67 (2007).

    Article  CAS  Google Scholar 

  3. Ashino, M. et al. Atomically resolved mechanical response of individual metallofullerene molecules confined inside carbon nanotubes. Nature Nanotech. 3, 337–341 (2008).

    Article  CAS  Google Scholar 

  4. Albers, B. J. et al. Three-dimensional imaging of short-range chemical forces with picometre resolution. Nature Nanotech. 4, 307–310 (2009).

    Article  CAS  Google Scholar 

  5. Gross, L., Mohn, F., Moll, N., Liljeroth, P. & Meyer, G. The chemical structure of a molecule resolved by atomic force microscopy. Science 325, 1110–1114 (2009).

    Article  CAS  Google Scholar 

  6. Vitali, L. et al. Portrait of the portential barrier at metal–organic nanocontacts. Nature Mater. 9, 320–323 (2010).

    Article  CAS  Google Scholar 

  7. Swart, I., Sonnleitner, T. & Repp, J. Charge state control of molecules reveals modification of the tunneling barrier with intramolecular contrast. Nano Lett. 11, 1580–1584 (2011).

    Article  CAS  Google Scholar 

  8. Sommerhalter, C., Matthes, T. W., Glatzel, T., Jäger-Waldau, A. & Lux-Steiner, M. C. High-sensitivity quantitative Kelvin probe microscopy by noncontact ultra-high-vacuum atomic force microscopy. Appl. Phys. Lett. 75, 286–288 (1999).

    Article  CAS  Google Scholar 

  9. Barth, C. & Henry, C. R. Surface double layer on (001) surfaces of alkali halide crystals: a scanning force microscopy study. Phys. Rev. Lett. 98, 136804 (2007).

    Article  Google Scholar 

  10. Gross, L. et al. Measuring the charge state of an adatom with noncontact atomic force microscopy. Science 324, 1428–1431 (2009).

    Article  CAS  Google Scholar 

  11. König, T. et al. Measuring the charge state of point defects on MgO/Ag(001). J. Am. Chem. Soc. 131, 17544–17545 (2009).

    Article  Google Scholar 

  12. Leoni, T. et al. Controlling the charge state of a single redox molecular switch. Phys. Rev. Lett. 106, 216103 (2011).

    Article  Google Scholar 

  13. Liljeroth, P., Repp, J. & Meyer, G. Current-induced hydrogen tautomerization and conductance switching of naphthalocyanine molecules. Science 317, 1203–1206 (2007).

    Article  CAS  Google Scholar 

  14. Grill, L. et al. Nano-architectures by covalent assembly of molecular building blocks. Nature Nanotech. 2, 687–691 (2007).

    Article  CAS  Google Scholar 

  15. Wang, W. et al. Manipulating localized molecular orbitals by single-atom contacts. Phys. Rev. Lett. 105, 126801 (2010).

    Article  Google Scholar 

  16. Mohn, F. et al. Reversible bond formation in a gold-atom–organic-molecule complex as a molecular switch. Phys. Rev. Lett. 105, 266102 (2010).

    Article  Google Scholar 

  17. Nonnenmacher, M., O'Boyle, M. P. & Wickramasinghe, H. K. Kelvin probe force microscopy. Appl. Phys. Lett. 58, 2921–2923 (1991).

    Article  Google Scholar 

  18. Burke, S. A. et al. Determination of the local contact potential difference of PTCDA on NaCl: a comparison of techniques. Nanotechnology 20, 264012 (2009).

    Article  CAS  Google Scholar 

  19. Sadewasser, S. et al. New insights on atomic-resolution frequency-modulation Kelvin-probe force-microscopy imaging of semiconductors. Phys. Rev. Lett. 103, 266103 (2009).

    Article  Google Scholar 

  20. Enevoldsen, G. H., Glatzel, T., Christensen, M. C., Lauritsen, J. V. & Besenbacher, F. Atomic scale Kelvin probe force microscopy studies of the surface potential variations on the TiO2 (110) surface. Phys. Rev. Lett. 100, 236104 (2008).

    Article  CAS  Google Scholar 

  21. Bocquet, F., Nony, L., Loppacher, C. & Glatzel, T. Analytical approach to the local contact potential difference on (001) ionic surfaces: implications for Kelvin probe force microscopy. Phys. Rev. B 78, 035410 (2008).

    Article  Google Scholar 

  22. Kawai, S., Glatzel, T., Hug, H-J. & Meyer, E. Atomic contact potential variations of Si(111)-7×7 analysed by Kelvin probe force microscopy. Nanotechnology 21, 245704 (2010).

    Article  Google Scholar 

  23. Masago, A., Tsukada, M. & Shimizu, M. Simulation method of Kelvin probe force microscopy at nanometer range and its application. Phys. Rev. B 82, 195433 (2010).

    Article  Google Scholar 

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

    Article  Google Scholar 

  25. Gross, L. et al. High-resolution molecular orbital imaging using a p-wave STM tip. Phys. Rev. Lett. 107, 086101 (2011).

    Article  Google Scholar 

  26. Gross, L. et al. Organic structure determination using atomic-resolution scanning probe microscopy. Nature Chem. 2, 821–825 (2010).

    Article  CAS  Google Scholar 

  27. Bartels, L., Meyer, G. & Rieder, K-H. Controlled vertical manipulation of single CO molecules with the scanning tunneling microscope: a route to chemical contrast. Appl. Phys. Lett. 71, 213–215 (1997).

    Article  CAS  Google Scholar 

  28. Jäckel, F. et al. Investigating molecular charge transfer complexes with a low temperature scanning tunneling microscope. Phys. Rev. Lett. 100, 126102 (2008).

    Article  Google Scholar 

  29. Tao, C. et al. Spatial resolution of a type II heterojunction in a single bipolar molecule. Nano Lett. 9, 3963–3967 (2009).

    Article  CAS  Google Scholar 

  30. Mohn, F., Gross, L. & Meyer, G. Measuring the short-range force field above a single molecule with atomic resolution. Appl. Phys. Lett. 99, 053106 (2011).

    Article  Google Scholar 

  31. CPMD, v.3.15 (copyright IBM Corp. 1990–2011, copyright MPI für Festkörperforschung Stuttgart 1997–2001).

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Acknowledgements

The authors thank J. Repp, R. Allenspach and W. Riess for helpful comments. Financial support from EU projects Herodot and ARTIST, as well as the ERC Advanced Grant CEMAS, is gratefully acknowledged.

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Contributions

F.M., L.G. and G.M. performed the experiments. F.M. and N.M. carried out the DFT calculations. F.M. wrote the manuscript. All authors discussed the results and commented on the manuscript.

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Correspondence to Fabian Mohn.

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The authors declare no competing financial interests.

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Mohn, F., Gross, L., Moll, N. et al. Imaging the charge distribution within a single molecule. Nature Nanotech 7, 227–231 (2012). https://doi.org/10.1038/nnano.2012.20

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