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arXiv · 1908.11129

Unhiding a concealed resonance by multiple Kondo transitions in a quantum dot

Aritra Lahiri·Tokuro Hata·Sergey Smirnov·Meydi Ferrier·Tomonori Arakawa·Michael Niklas·Magdalena Marganska·Kensuke Kobayashi·Milena Grifoni
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Abstract

Kondo correlations are responsible for the emergence of a zero-bias peak in the low temperature differential conductance of Coulomb blockaded quantum dots. In the presence of a global SU(2)$\otimes$SU(2) symmetry, which can be realized in carbon nanotubes, they also inhibit inelastic transitions which preserve the Kramers pseudospins associated to the symmetry. We report on magnetotransport experiments on a Kondo correlated carbon nanotube where resonant features at the bias corresponding to the pseudospin-preserving transitions are observed. We attribute this effect to a simultaneous enhancement of pseudospin-non-preserving transitions occurring at that bias. This process is boosted by asymmetric tunneling couplings of the two Kramers doublets to the leads and by asymmetries in the potential drops at the leads. Hence, the present work discloses a fundamental microscopic mechanisms ruling transport in Kondo systems far from equilibrium.

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Aritra Lahiri, Tokuro Hata, Sergey Smirnov, Meydi Ferrier, Tomonori Arakawa, Michael Niklas, Magdalena Marganska, Kensuke Kobayashi, Milena Grifoni. 2019-08-29. Unhiding a concealed resonance by multiple Kondo transitions in a quantum dot. https://doi.org/10.1103/physrevb.101.041102

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