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.

  • Letter
  • Published:

Probing the conductance superposition law in single-molecule circuits with parallel paths

Abstract

According to Kirchhoff's circuit laws, the net conductance of two parallel components in an electronic circuit is the sum of the individual conductances. However, when the circuit dimensions are comparable to the electronic phase coherence length, quantum interference effects play a critical role1, as exemplified by the Aharonov–Bohm effect in metal rings2,3. At the molecular scale, interference effects dramatically reduce the electron transfer rate through a meta-connected benzene ring when compared with a para-connected benzene ring4,5. For longer conjugated and cross-conjugated molecules, destructive interference effects have been observed in the tunnelling conductance through molecular junctions6,7,8,9,10. Here, we investigate the conductance superposition law for parallel components in single-molecule circuits, particularly the role of interference. We synthesize a series of molecular systems that contain either one backbone or two backbones in parallel, bonded together cofacially by a common linker on each end. Single-molecule conductance measurements and transport calculations based on density functional theory show that the conductance of a double-backbone molecular junction can be more than twice that of a single-backbone junction, providing clear evidence for constructive interference.

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

Access options

Buy this article

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

Figure 1: Single-molecule circuits containing one and two conducting backbones connected in parallel.
Figure 2: STM break-junction measurements of single-molecule conductance.
Figure 3: Calculated transmission properties comparing a double-backbone circuit with an idealized, single-backbone circuit.

Similar content being viewed by others

References

  1. Beenakker, C. W. J. & van Houten, H. Quantum transport in semiconductor nanostructures. Solid State Phys. 44, 1–228 (1991).

    Article  Google Scholar 

  2. Aharonov, Y. & Bohm, D. Significance of electromagnetic potentials in the quantum theory. Phys. Rev. 115, 485–491 (1959).

    Article  Google Scholar 

  3. Webb, R. A., Washburn, S., Umbach, C. P. & Laibowitz, R. B. Observation of h/e Aharonov–Bohm oscillations in normal-metal rings. Phys. Rev. Lett. 54, 2696–2699 (1985).

    Article  CAS  Google Scholar 

  4. Sautet, P. & Joachim, C. Electronic interference produced by a benzene embedded in a polyacetylene chain. Chem. Phys. Lett. 153, 511–516 (1988).

    Article  CAS  Google Scholar 

  5. Patoux, C., Coudret, C., Launay, J-P., Joachim, C. & Gourdon, A. Topological effects on intramolecular electron transfer via quantum interference. Inorg. Chem. 36, 5037–5049 (1997).

    Article  CAS  Google Scholar 

  6. Mayor, M. et al. Electric current through a molecular rod—relevance of the position of the anchor groups. Angew. Chem. Int. Ed. 42, 5834–5838 (2003).

    Article  CAS  Google Scholar 

  7. Kiguchi, M., Nakamura, H., Takahashi, Y., Takahashi, T. & Ohto, T. Effect of anchoring group position on formation and conductance of a single disubstituted benzene molecule bridging Au electrodes: change of conductive molecular orbital and electron pathway. J. Phys. Chem. C 114, 22254–22261 (2010).

    Article  CAS  Google Scholar 

  8. Fracasso, D., Valkenier, H., Hummelen, J. C., Solomon, G. C. & Chiechi, R. C. Evidence for quantum interference in SAMs of arylethynylene thiolates in tunneling junctions with eutectic Ga–In (EGaIn) top-contacts. J. Am. Chem. Soc. 133, 9556–9563 (2011).

    Article  CAS  Google Scholar 

  9. Guedon, C. M. et al. Observation of quantum interference in molecular charge transport. Nature Nanotech. 7, 305–309 (2012).

    Article  CAS  Google Scholar 

  10. Aradhya, S. V. et al. Dissecting contact mechanics from quantum interference in single-molecule junctions of stilbene derivatives. Nano Lett. 12, 1643–1647 (2012).

    Article  CAS  Google Scholar 

  11. Yaliraki, S. N. & Ratner, M. A. Molecule–interface coupling effects on electronic transport in molecular wires. J. Chem. Phys. 109, 5036–5043 (1998).

    Article  CAS  Google Scholar 

  12. Magoga, M. & Joachim, C. Conductance of molecular wires connected or bonded in parallel. Phys. Rev. B 59, 16011–16021 (1999).

    Article  CAS  Google Scholar 

  13. Lang, N. D. & Avouris, P. Electrical conductance of parallel atomic wires. Phys. Rev. B 62, 7325–7329 (2000).

    Article  CAS  Google Scholar 

  14. Liu, R., Ke, S-H., Baranger, H. U. & Yang, W. Intermolecular effect in molecular electronics. J. Chem. Phys. 122, 044703 (2005).

    Article  Google Scholar 

  15. Landau, A., Kronik, L. & Nitzan, A. Cooperative effects in molecular conduction. J. Comput. Theor. Nanosci. 5, 535–544 (2008).

    Article  CAS  Google Scholar 

  16. Reuter, M. G., Seideman, T. & Ratner, M. A. Molecular conduction through adlayers: cooperative effects can help or hamper electron transport. Nano Lett. 11, 4693–4696 (2011).

    Article  CAS  Google Scholar 

  17. Park, Y. S. et al. Contact chemistry and single-molecule conductance: a comparison of phosphines, methyl sulfides, and amines. J. Am. Chem. Soc. 129, 15768–15769 (2007).

    Article  CAS  Google Scholar 

  18. Park, Y. S. et al. Frustrated rotations in single-molecule junctions. J. Am. Chem. Soc. 131, 10820–10821 (2009).

    Article  CAS  Google Scholar 

  19. Xu, B. Q. & Tao, N. J. Measurement of single-molecule resistance by repeated formation of molecular junctions. Science 301, 1221–1223 (2003).

    Article  CAS  Google Scholar 

  20. Quek, S. Y. et al. Mechanically controlled binary conductance switching of a single-molecule junction. Nature Nanotech. 4, 230–234 (2009).

    Article  CAS  Google Scholar 

  21. Kamenetska, M. et al. Conductance and geometry of pyridine-linked single-molecule junctions. J. Am. Chem. Soc. 132, 6817–6821 (2010).

    Article  CAS  Google Scholar 

  22. Martin, C. A. et al. Fullerene-based anchoring groups for molecular electronics. J. Am. Chem. Soc. 130, 13198–13199 (2008).

    Article  CAS  Google Scholar 

  23. Quek, S. Y. et al. Amine-gold linked single-molecule circuits: experiment and theory. Nano Lett. 7, 3477–3482 (2007).

    Article  CAS  Google Scholar 

  24. Quek, S. Y., Choi, H. J., Louie, S. G. & Neaton, J. B. Length dependence of conductance in aromatic single-molecule junctions. Nano Lett. 9, 3949–3953 (2009).

    Article  CAS  Google Scholar 

  25. Strange, M., Rostgaard, C., Hakkinen, H. & Thygesen, K. S. Self-consistent GW calculations of electronic transport in thiol- and amine-linked molecular junctions. Phys. Rev. B 83, 115108 (2011).

    Article  Google Scholar 

  26. Venkataraman, L. et al. Single-molecule circuits with well-defined molecular conductance. Nano Lett. 6, 458–462 (2006).

    Article  CAS  Google Scholar 

  27. Soler, J. M. et al. The SIESTA method for ab initio order-N materials simulation. J. Phys. Condens. Matter 14, 2745–2779 (2002).

    Article  CAS  Google Scholar 

  28. Brandbyge, M., Mozos, J. L., Ordejon, P., Taylor, J. & Stokbro, K. Density-functional method for nonequilibrium electron transport. Phys. Rev. B 65, 165401 (2002).

    Article  Google Scholar 

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

    Article  CAS  Google Scholar 

  30. Paulsson, M. & Brandbyge, M. Transmission eigenchannels from nonequilibrium Green's functions. Phys. Rev. B 76, 115117 (2007).

    Article  Google Scholar 

Download references

Acknowledgements

This work was supported primarily by the Nanoscale Science and Engineering Initiative of the National Science Foundation (NSF, CHE-0641523), the New York State Office of Science, Technology, and Academic Research (NYSTAR) and an NSF Career Award to L.V. (CHE-07-44185). L.V. also thanks the Packard Foundation for support. This work was carried out in part at the Center for Functional Nanomaterials, Brookhaven National Laboratory, which is supported by the US Department of Energy, Office of Basic Energy Sciences (contract no. DE-AC02-98CH10886). R.S. acknowledges financial support from the Canadian postdoctoral fellowship FQRNT programme. S.T.S. acknowledges support from an Arun Guthikonda Memorial graduate fellowship. The authors thank the NSF (CHE-0619638) for the acquisition of an X-ray diffractometer, and G. Parkin and W. Sattler for obtaining our crystal structures.

Author information

Authors and Affiliations

Authors

Contributions

The experiments were conceived by R.S., S.S., M.K., R.B. and L.V. Theory and calculations were conceived by H.V. and M.S.H. Synthesis and chemical analysis were performed by R.S. and S.S. Conductance measurements and analysis were performed by M.K and L.V. Calculations were performed by H.V. The manuscript was written by H.V., L.V. and M.S.H., with comments and input from all other authors.

Corresponding authors

Correspondence to R. Breslow, L. Venkataraman or M.S. Hybertsen.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary information

Supplementary information (PDF 7417 kb)

Rights and permissions

Reprints and permissions

About this article

Cite this article

Vazquez, H., Skouta, R., Schneebeli, S. et al. Probing the conductance superposition law in single-molecule circuits with parallel paths. Nature Nanotech 7, 663–667 (2012). https://doi.org/10.1038/nnano.2012.147

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nnano.2012.147

This article is cited by

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