Su(4) mixed valence regime in carbon nanotube quantum dots

Published

Journal Article

We study the evolution of conductance regimes in carbon nanotubes with doubly degenerate orbitals ("shells") by controlling the contact transparency within the same sample. For sufficiently open contacts, Kondo behavior is observed for 1, 2, and 3 electrons in the topmost shell. As the contacts are opened more, the sample enters the "mixed valence" regime, where different charge states are strongly hybridized by electron tunneling. Here, the conductance as a function of gate voltage shows pronounced modulations with a period of four electrons, and all single-electron features are washed away at low temperature. We successfully describe this behavior by a simple formula with no fitting parameters. Finally, we find a surprisingly small energy scale that controls the temperature evolution of conductance and the tunneling density of states in the mixed valence regime. © 2007 Elsevier B.V. All rights reserved.

Full Text

Duke Authors

Cited Authors

  • Makarovski, A; Finkelstein, G

Published Date

  • April 1, 2008

Published In

Volume / Issue

  • 403 / 5-9

Start / End Page

  • 1555 - 1557

International Standard Serial Number (ISSN)

  • 0921-4526

Digital Object Identifier (DOI)

  • 10.1016/j.physb.2007.10.367

Citation Source

  • Scopus