Numerical renormalization-group study of particle-hole symmetry breaking in two-channel Kondo problem: Effect of repulsion among conduction electrons and potential scattering

Particle-hole symmetry breaking perturbation in the two-channel pseudospin Kondo problem is studied by the numerical renormalization-group method. It is shown that the repulsion among conduction electrons at the impurity site and the single particle potential are relevant perturbations against the conventional non-Fermi-liquid fixed point. Although the repulsion (potential) with realistic strength prevents the overscreening of the pseudospin, it induces in turn a real spin, which is also overscreened again. Thus the real spin susceptibility becomes anomalous, contrary to the conventional two-channel Kondo problem.