Kondo resonance for orbitally degenerate systems
  Formation of the Kondo state in general two-band Anderson model has been investigated within the numerical renormalization group (NRG) calculations. The Abrikosov-Suhl resonance is essentially asymmetric for the model with one electron per impurity (quarter filling case) in contrast with the one-band case. An external magnetic (pseudo-magnetic) field breaking spin (orbital) degeneracy leads to asymmetric splitting and essential broadening of the many-body resonance. Unlike the standard Anderson model, the ``spin up'' Kondo peak is pinned against the Fermi level, but not suppressed by magnetic field. 
A.K. Zhuravlev, V.Yu. Irkhin, M.I. Katsnelson, A.I. Lichtenstein