Lucignano P, Fabrizio M, Tagliacozzo A

The zero bias anomaly in the conductance due to Kondo correlations in a quantum dot at Coulomb blockade with an even number of electrons has been only clearly experimentally seen at the singlet-triplet crossing. However, S = 1 Kondo correlations should also be present in a dot in the absence of magnetic field if Hund's rule enforces a triplet ground state. We propose that the elusive appearance of the S = 1 Rondo anomaly in semiconductor quantum dots is due to spin-orbit interactions, which we find to be a relevant perturbation of the Kondo fixed point in the NRG flow. (C) 2009 Elsevier B.V. All rights reserved.