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

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.

5 pages, 3 figures; revised version as published

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Cited by in corpus (4)

• Spintronic magnetic anisotropy
• Thermopower of an SU(4) Kondo resonance under an SU(2) symmetry-breaking field
• Interplay of Coulomb interaction and spin-orbit effects in multi-level quantum dots
• Cotunneling renormalization in carbon nanotube quantum dots