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arXiv · 1204.6718

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·T. Fujisawa
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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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K. Grove-Rasmussen, S. Grap, J. Paaske, K. Flensberg, S. Andergassen, V. Meden, H. I. Jørgensen, K. Muraki, T. Fujisawa. 2012-04-30. Magnetic-Field Dependence of Tunnel Couplings in Carbon Nanotube Quantum Dots. https://doi.org/10.1103/physrevlett.108.176802

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