Infrared Divergence and Non-Fermi Liquid in Multichannel Degenerate Anderson Model

Abstract

As a straightforward extention of the study on infrared divergences in pseudo-particle spectra in the single-channel degenerate impurity Anderson model, those of the multichannel model are examined with use of the expansion from the large limit of the spin-orbital degeneracy N . Analysis with the most divergent terms in the expansion shows that exponents of spectra of the slave boson and the pseudo-fermion in the M -channel model with 1 ≤ M ≪ N are given respectively by 1- n f 2 M / N and (2 n f - n f 2 ) M / N , where n f is the average number of localized electrons at the impurity site. When M =1, the results recover those obtained earlier in the single channel model. In the limits, n f →1 and M -2 ≪1, these results tend to those obtained by the non-crossing approximation (NCA) study. It also shows that the scattering rate of the conduction electrons in the M -channel model includes infrared divergent terms proportional to (1- n f )(1- M -2 ) in contrast to the absence of infrared divergent terms in the...