Non-equilibrium singlet–triplet Kondo effect in carbon nanotubes

By J. Paaske, Achim Rosch, P. Wölfle, Nadya Mason, Charles Marcus, Jesper Nygård. 2006

148 citations recorded by the source corpus.

The Kondo effect is a many-body phenomenon arising due to conduction electrons scattering off a localized spin1. Coherent spin-flip scattering off such a quantum impurity correlates the conduction electrons, and at low temperature this leads to a zero-bias conductance anomaly2,3. This has become a common signature in bias spectroscopy of single-electron transistors, observed in GaAs quantum dots4,5,6,7,8,9 as well as in various single-molecule transistors10,11,12,13,14,15. Although the zero-bias Kondo effect is well established, the extent to which Kondo correlations persist in non-equilibrium situations where inelastic processes induce decoherence remains uncertain. Here we report on a pronounced conductance peak observed at finite bias voltage in a carbon-nanotube quantum dot in the spin-singlet ground state. We explain this finite-bias conductance anomaly by a non-equilibrium Kondo effect involving excitations into a spin-triplet state. Excellent agreement between calculated and measured nonlinear conductance is obtained, thus strongly supporting the correlated nature of this non-equilibrium resonance.

Subfields: Atomic and Molecular Physics, and Optics, Electrical and Electronic Engineering, Materials Chemistry

View Paper: https://www.semanticscholar.org/paper/2d189853b4d859ea4bbfaab2347b7f0c82917a1a

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In Atomic and Molecular Physics, and Optics

In Electrical and Electronic Engineering

In Materials Chemistry

Citations in the corpus

Advances and challenges in single-molecule electron transport (2019, background): “In the regime (i) there are inelastic steps corresponding to singlet-triplet excitations (Korytár et al., 2012; Paaske et al., 2006).”
Spins in few-electron quantum dots (2006, background): “Therefore, the triplet states change the second-order (cotunneling) currents at three values of VSD if the ground state is a singlet 7 (Paaske et al., 2006).”
Molecular transport junctions: vibrational effects (2006, background): “Stronger molecule–leads coupling relevant (for example) to the observation of non-equilibrium Kondo resonance [395] should be treated at a more sophisticated level.”