Anderson impurity model: Vertex corrections within the finite U non-crossing approximation

P. ROURA BAS; V. VILDOSOLA; L. O. MANUEL; A. M. LLOIS

Centro Atómico Constituyentes, Buenos Aires

Workshop; At the Frontiers of Condensed Matter IV; 2008

Comisión Nacional de Energía Atómica (CNEA)

We revise the simplest possible approximations to solve numerically the vertex equations for the Single Impurity Anderson Model (SIAM) within the finite U Non-Crossing Approximation (UNCA), considering the self energies at lowest order in the 1/N diagrammatic expansion. We introduce an approximation to the vertex corrections that includes the double energy dependence and compare it with an approximation (NCAf2v) that neglects a second energy argument. Finally, we analyse the influence of the different approximations on the estimated Kondo scale for simple electronic  models.