Negative Differential Resistance in Covalently-Bridged Carbon Nanotube Junctions

ORAL

Abstract

Recently, negative differential resistance (NDR) was observed in IV characteristics of carbon atomic wires connected across multi-wall carbon nanotubes.$^{1}$ Motivated by these results, we calculated IV characteristics of carbon atomic wires covalently bridging capped single-wall armchair carbon nanotubes using an \textit{ab-initio} scattering-state formalism based on density functional theory.$^{2}$ Our calculations for carbon chains with an odd number of atoms yield currents orders of magnitude larger than that of even chains, demonstrating clear even-odd behavior. We also observe NDR for odd chains and shorter even chains, in agreement with experiment. The current drop at higher voltages is attributed to an energy mismatch between localized nanotube ``cap states'' on different leads, possibly a generic feature of carbon nanotube molecular junctions. [1] T. Yuzvinsky \textit{et al., Nano Lett.} 10.1021/nl061671j (2006). [2] H.J. Choi, M.L. Cohen and S.G. Louie, to be published. This work supported by NSF Grant No DMR04-39768 and DOE Contract No DE-AC02-05CH11231. Computational resources from NERSC and SDSC.

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Authors

  • K.H. Khoo

    Dept of Physics UC Berkeley, Mat Sci Div LBNL

  • Young-Woo Son

    Korea Institute for Advanced Study, Dept of Physics UC Berkeley, Mat Sci Div LBNL, School of Computational Sciences, Korea Institute for Advanced Study, Seoul 130-722, Korea

  • Marvin Cohen

    Dept of Physics UC Berkeley, Mat Sci Div LBNL, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, UC Berkeley, Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, UC Berkeley \& LBNL, UC Berkeley and Lawrence Berkeley National Laboratory

  • J.B. Neaton

    The Molecular Foundry LBNL, Lawrence Berkeley National Laboratory

  • Steven Louie

    Molecular Foundry, Lawrence Berkeley National Laboratory and Department of Physics, University of California at Berkeley, Dept of Physics UC Berkeley, The Molecular Foundry LBNL, Mat Sci Div LBNL, Department of Physics, University of California at Berkeley and Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, UC Berkeley, Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Laboratory, University of California at Berkeley, University of California, Berkeley \& Lawrence Berkeley National Laboratory, University of California at Berkeley and Lawrence Berkeley National Lab, Department of Physics, University of California, Berkeley, and Materials Sciences Division, Lawrence Berkeley National Laboratory