Topological quantum phase transition between Fermi liquid phases in an Anderson impurity model

ALIGIA, A.; PABLO ROURA-BAS; BLESIO, GERMÁN; LUIS O. MANUEL

Buenos Aires

Workshop; Novel topics in Condensed Matter Physics; 2018

International Center for Advanced Studies, UNSAM

We study a generalized Anderson model that mixes two localized configurations -one formed by two degenerate doublets and the other by a triplet with single-ion anisotropy D- by means of two degenerate conduction channels. The model has been derived for a single Ni impurity embedded into an O-doped Au chain. Using the numerical renormalization group, we find a topological quantum phase transition, at a finite value Dc, between two regular Fermi liquid phases of high (low) conductance and topological number 2 I_L/pi = 0 (-1) for D < Dc (D > Dc), where I_L is the well-known Luttinger integral. At finite temperature the two phases are separated by a non-Fermi liquid phase with fractional impurity entropy and other properties which remind those of the two-channel Kondo model.