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Multi-wall carbon nanotubes as quantum dots

M. R. Buitelaar·A. Bachtold·T. Nussbaumer·M. Iqbal·C. Schoenenberger
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Abstract

We have measured the differential conductance dI/dV of individual multi-wall carbon nanotubes (MWNT) of different lengths. A cross-over from wire-like (long tubes) to dot-like (short tubes) behavior is observed. dI/dV is dominated by random conductance fluctuations (UCF) in long MWNT devices (L=2...7 $μm$), while Coulomb blockade and energy level quantization are observed in short ones (L=300 nm). The electron levels of short MWNT dots are nearly four-fold degenerate (including spin) and their evolution in magnetic field (Zeeman splitting) agrees with a g-factor of 2. In zero magnetic field the sequential filling of states evolves with spin S according to S=0 -> 1/2 -> 0... In addition, a Kondo enhancement of the conductance is observed when the number of electrons on the tube is odd.

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M. R. Buitelaar, A. Bachtold, T. Nussbaumer, M. Iqbal, C. Schoenenberger. 2001-10-03. Multi-wall carbon nanotubes as quantum dots. https://doi.org/10.1103/physrevlett.88.156801

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