As the scale of microelectronic engineering continues to shrink, interest has focused on the nature of electron transport through essentially one-dimensional nanometre-scale channels such as quantum wires1 and carbon nanotubes2,3. Quantum point contacts (QPCs) are structures (generally metallic) in which a ‘neck’ of atoms just a few atomic diameters wide (that is, comparable to the conduction electrons' Fermi wavelength) bridges two electrical contacts. They can be prepared by contacting a metal surface witha scanning tunnelling microscope (STM)4,5,6,7 and by other methods8,9,10,11,12, and typically display a conductance quantized in steps of 2e2/h(∼13 kΩ−1)13,14, where e is the electron charge and h is Planck's constant. Here we report conductance measurements on metal QPCs prepared with an STM that we can simultaneously image using an ultrahigh-vacuum electron microscope, which allows direct observation of the relation between electron transport and structure. We observe strands of gold atoms that are about one nanometre long and one single chain of gold atoms suspended between the electrodes. We can thus verify that the conductance of a single strand of atoms is 2e2/h and that the conductance of a double strand is twice as large, showing that equipartition holds for electron transport in these quantum systems.
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
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).
Iijima, S. Helical microtubules of graphitic carbon. Nature 354, 56–58 (1991).
Bockrath, M. et al. Single-electron transport in ropes of carbon nanotubes. Science 275, 1922–1925 (1997).
Agrait, N., Rodrigo, J. G. & Vieira, S. Conductance steps and quantization in atomic-size contacts. Phys. Rev. B 47, 12345–12348 (1993).
Pascual, J. I. et al. Properties of metallic nanowires: from conductance quantization to localization. Science 267, 1793–1795 (1995).
Olesen, L. et al. Quantized conductance in an atom-size point contact. Phys. Rev. Lett. 72, 2251–2254 (1994).
Costa-Krämer, J. L. et al. Conductance quantization in nanowires formed between micro- and macroscopic metallic electrodes. Phys. Rev. B 55, 5416–5424 (1997).
Muller, C. J., Krans, J. M., Todorov, T. N. & Reed, M. A. Quantization effects in the conductance of metallic contacts at room temperature. Phys. Rev. B 53, 1022–1025 (1996).
Landman, U., Luedtke, W. D., Salisbury, B. E. & Whetten, R. L. Reversible manipulations of room-temperature mechanical and quantum transport properties in nanowire junctions. Phys. Rev. Lett. 77, 1362–1365 (1996).
Costa-Krämer, J. L., García, N., García-Mochales, P. & Serena, P. A. Nanowire formation in macroscopic metallic contacts: quantum mechanical conductance tapping a table top. Surf. Sci. 342, L1144–L1149 (1995).
Hansen, K., Lægsgaard, E., Stensgaard, I. & Besenbacher, F. Quantized conductance in relays. Phys. Rev. B 56, 2208–2220 (1997).
Yasuda, H. & Sakai, A. Conductance of atomic-scale gold contacts under high-bias voltages. Phys. Rev. B 56, 1069–1072 (1997).
van Wees, B. J. et al. Quantized conductance of point contacts in a two-dimensional electron gas. Phys. Rev. Lett. 60, 848–850 (1988).
Wharam, D. A. et al. One-dimensional transport and the quantisation of the ballistic resistance. J.Phys.C 21, L209–L214 (1988).
Cowley, J. M. in Diffraction Physics 62–63 (Elsevier, Amsterdam, (1975).
Kondo, Y. & Takayanagi, K. Gold nanobridge stabilized by surface structure. Phys. Rev. Lett. 79, 3455–3458 (1997).
Maxwell, J. C. in A Treatise on Electricity and Magnetism (Clarendon, Oxford, (1904).
Sharvin, Y. V. Apossible method for studying fermi surfaces. Sov. Phys. JETP 21, 655–656 (1965).
Landauer, R. Spatial variation of currents and fields due to localized scatterers in metallic conduction. IBM J. Rev. Dev. 1, 223–231 (1957).
Kubo, R. Statistical-mechanical theory of irreversible process. I. General theory and simple applications to magnetic and conduction problems. J. Phys. Soc. Jpn 12, 570–586 (1957).
Landman, U., Luedtke, W. D., Burnham, N. A. & Colton, R. J. Atomic mechanics and dynamics of adhesion, nanoindentation, and fracture. Science 248, 454–461 (1990).
Bratkovsky, A. M., Sutton, A. P. & Todorov, T. N. Conditions for conductance quantization in realistic models of atomic-scale metallic contacts. Phys. Rev. B 52, 5036–5051 (1995).
Sørensen, M. R., Brandbyge, M. & Jacobsen, K. W. Mechanical deformation of atomic-scale metallic contacts: structure and mechanisms. Phys. Rev. B 57, 3283–3294 (1998).
About this article
Cite this article
Ohnishi, H., Kondo, Y. & Takayanagi, K. Quantized conductance through individual rows of suspended gold atoms. Nature 395, 780–783 (1998). https://doi.org/10.1038/27399
Theoretical studies on the electronic and optoelectronic properties of DNA/RNA hybrid-metal complexes
Correction to “Unsupervised Segmentation-Based Machine Learning as an Advanced Analysis Tool for Single Molecule Break Junction Data”
The Journal of Physical Chemistry C (2020)
Physical Review B (2020)
Physica E: Low-dimensional Systems and Nanostructures (2020)