Kondo effect in the Kohn–Sham conductance of multiple-level quantum dots

Authors

  • Gianluca Stefanucci,

    Corresponding author
    1. Dipartimento di Fisica, Università di Roma Tor Vergata, Via della Ricerca Scientifica 1, 00133 Rome, Italy
    2. INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati, Italy
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    • Also affiliated with: European Theoretical Spectroscopy Facility (ETSF)
  • Stefan Kurth

    1. Nano-Bio Spectroscopy Group, Dpto. de Fisica de Materiales, Universidad del Pais Vasco UPV/EHU, Avenida Tolosa 72, 20018 San Sebastián, Spain
    2. IKERBASQUE, Basque Foundation for Science, 48011 Bilbao, Spain
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    • Also affiliated with: European Theoretical Spectroscopy Facility (ETSF)

Abstract

At zero temperature, the Landauer formalism combined with static density functional theory is able to correctly reproduce the Kondo plateau in the conductance of the Anderson impurity model provided that an exchange-correlation potential is used which correctly exhibits steps at integer occupation. Here we extend this recent finding to multi-level quantum dots described by the constant-interaction model. We derive the exact exchange-correlation potential in this model for the isolated dot and deduce an accurate approximation for the case when the dot is weakly coupled to two leads. We show that at zero temperature and for non-degenerate levels in the dot we correctly obtain the conductance plateau for any odd number of electrons on the dot. We also analyze the case when some of the levels of the dot are degenerate and again obtain good qualitative agreement with results obtained with alternative methods. As in the case of a single level, for temperatures larger than the Kondo temperature, the Kohn–Sham conductance fails to reproduce the typical Coulomb blockade peaks. This is attributed to dynamical exchange-correlation corrections to the conductance originating from time-dependent density functional theory.

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