One-dimensional physics in transition-metal nanowires: Phases and   elementary excitations
  We used the Hartree-Fock approximation to classify the electronic phases that might occur in a transition metal nanowire. The important features of this situation are orbital degeneracy (or near-degeneracy) and interactions favoring locally high-spin configurations. In this circumstance, spin density wave and triplet superconductivity states are favored. If the interactions favor locally low-spin configurations as in the previously studied spin ladder systems, orbital density wave and singlet superconductivity are observed. 
Jun-ichi Okamoto, A. J. Millis
cond-mat.str-el