Ground-State Properties of Extended Two-Channel Kondo Model

抄録

Ground-state properties are examined for an extended two-channel Kondomodel where the Hilbert space of the localized states is extended to include a singlet state in addition to thedoublet states.By means of zero-th order variational wavefunctions with differentsymmetries, which are associated with the non-Fermi-liquid and theFermi-liquid ground states, we demonstrate that the channel exchange coupling via the localized singlet statestabilizes the Fermi-liquid wavefunction. The ground-state phase diagrams, which are in qualitative agreement with theprevious study performed by Koga and Shiba, are obtained.The comparison to the structure of the resultant wavefunctions suggests thata unique non-Fermi-liquid (Fermi-liquid) fixed point exists, irrespective ofthe localized ground state.