Magnetic-Field Dependence of Tunnel Couplings in Carbon Nanotube Quantum Dots

K. Grove-Rasmussen, S. Grap, J. Paaske, K. Flensberg, S. Andergassen, V. Meden, H. I. Jørgensen, K. Muraki, and T. Fujisawa
Phys. Rev. Lett. 108, 176802 – Published 26 April 2012
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Abstract

By means of sequential and cotunneling spectroscopy, we study the tunnel couplings between metallic leads and individual levels in a carbon nanotube quantum dot. The levels are ordered in shells consisting of two doublets with strong- and weak-tunnel couplings, leading to gate-dependent level renormalization. By comparison to a one- and two-shell model, this is shown to be a consequence of disorder-induced valley mixing in the nanotube. Moreover, a parallel magnetic field is shown to reduce this mixing and thus suppress the effects of tunnel renormalization.

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  • Received 1 September 2011

DOI:https://doi.org/10.1103/PhysRevLett.108.176802

© 2012 American Physical Society

Authors & Affiliations

K. Grove-Rasmussen1,2,*, S. Grap3, J. Paaske2, K. Flensberg2, S. Andergassen3,4, V. Meden3, H. I. Jørgensen2, K. Muraki1, and T. Fujisawa1,5

  • 1NTT Basic Research Laboratories, NTT Corporation, 3-1, Morinosato-Wakamiya, Atsugi 243-0198, Japan
  • 2Niels Bohr Institute and Nano-Science Center, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
  • 3Institut für Theorie der Statistischen Physik and JARA-Fundamentals of Future Information Technology, RWTH Aachen University, 52056 Aachen, Germany
  • 4Faculty of Physics, University of Vienna, Boltzmanngasse 5, 1090 Wien, Austria
  • 5Department of Physics, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro 152-8551, Japan

  • *k_grove@fys.ku.dk

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Issue

Vol. 108, Iss. 17 — 27 April 2012

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