Transport and Charge Sensing in $^{12}$C and $^{13}$C Carbon Nanotube Double Quantum Dots

ORAL

Abstract

We report measurements of gate-defined carbon nanotube double quantum dot devices with a charge sensor fabricated on the same nanotube. The methane used during growth controls the $^{13}$C content of the nanotubes. $^{12}$C nuclei have zero nuclear spin, and $^{13}$C nuclei have spin 1/2. We compare samples with natural abundance (1\%) and enriched (99\%) $^{13}$C content. A strong isotope effect is observed in the magnetic field dependence of transport at finite bias. Fast control of these devices is demonstrated using a pulsed-gate technique.

*We acknowledge support from the NSF (EIA-0210736). HC acknowledges the NSF GRFP, and DM acknowledges MEC-Spain (FPU AP2005-0720).

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Authors

  • Hugh Churchill

    • Harvard University

  • David Marcos

    • Harvard University/Consejo Superior de Investigaciones Cientificas
    • CSIC

  • Andrew Bestwick

    • Harvard University

  • Jennifer Harlow

    • Harvard University

  • Carolyn Stwertka

    • Harvard University/Middlebury College

  • Susan Watson

    • Harvard University/Middlebury College

  • Charles Marcus

    • Harvard University
    • Department of Physics, Harvard University