Reprint of: Kondo effect in a carbon nanotube with spin–orbit interaction and valley mixing: A DM-NRG study

Davide Mantelli, Cătălin Paşcu Moca, G. Zaránd, Milena Grifoni

Research output: Contribution to journalArticle


We investigate the effects of spin–orbit interaction (SOI) and valley mixing on the transport and dynamical properties of a carbon nanotube (CNT) quantum dot in the Kondo regime. As these perturbations break the pseudo-spin symmetry in the CNT spectrum but preserve time-reversal symmetry, they induce a finite splitting Δ between formerly degenerate Kramers pairs. Correspondingly, a crossover from the SU(4) to the SU(2)-Kondo effect occurs as the strength of these symmetry breaking parameters is varied. Clear signatures of the crossover are discussed both at the level of the spectral function as well as of the conductance. In particular, we demonstrate numerically and support with scaling arguments that the Kondo temperature scales inversely with the splitting Δ in the crossover regime. In presence of a finite magnetic field, time reversal symmetry is also broken. We investigate the effects of both parallel and perpendicular fields (with respect to the tube's axis) and discuss the conditions under which Kondo revivals may be achieved.

Original languageEnglish
Pages (from-to)39-49
Number of pages11
JournalPhysica E: Low-Dimensional Systems and Nanostructures
Publication statusPublished - Aug 1 2016


  • Carbon nanotubes
  • Density matrix numerical renormalization group
  • Kondo effect
  • Strong coupling

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Atomic and Molecular Physics, and Optics
  • Electronic, Optical and Magnetic Materials

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