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H. O. H. Churchill, D. Marcos, F. Kuemmeth, S. K. Watson, and C. Marcus.
Recent advances in fabrication techniques have made it possible to create tunable quantum dots on semiconducting nanowires and carbon nanotubes. In particular, double-dots formed on carbon nanotubes [1-3], are interesting candidates for the implementation of qubits based on their unique electronic structure as well as the weakness of nuclear and spin-orbit coupling in the predominantly C12 host. Here we report measurements obtained from an integrated double dot and charge sensor [4,5] fabricated from a single carbon nanotube. The conductance through the single dot allows us to monitor the charge state of the double dot even if it is decoupled from the leads. We also demonstrate fast manipulation of the double dot using pulsed-gates techniques. [1] M. J. Biercuk et al., Nano Letters 5, 1267 (2005). [2] S. Sapmaz et al., Semiconductor science and technology, 21(11), S52 (2006). [3] M. R. Graeber et al., Phys. Rev. B 74, 075427 (2006). [4] Y. Hu, H. O. H. Churchill et al., Nature Nanotechnology 2, 622 (2007). [5] M. J. Biercuk et al., Phys. Rev. B 73, 201402(R) (2006). The NSF-NIRT (EIA-0210736) and the Harvard Center for Nanoscale Systems are acknowledged. |
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