Overscreening-unscreening transition in the two-channel Kondo model induced by electron-electron repulsion

Abstract

The effects of the repulsion between the electrons on the two-channel Kondo problem are studied by use of bosonization technique. Following Emery and Kivelson, we define a special case in the spin density wave sector, in which the impurity spin is actually detached from the dynamics of the electrons. The model is thus mapped to a boundary sine-Gordon system. We find that, in the case of breakdown of rotational symmetry in spin space, the repulsion will induce a overscreening-unscreening transition in the system.