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oxides; electrical properties
Abstract:
We calculate the self-energy at weak-coupling for the t-t' Hubbard
model within the one-loop functional RG approach. At van Hove (vH) band
fillings the quasiparticle (qp) concept is found invalid at k(F)=(pi,
0). At low temperature the qp weight along the Fermi surface
continuously vanishes from a finite value at the zone diagonal towards
the (pi, 0) point. Away from vH band fillings the qp peak is formed
inside a pseudogap of size Delta, and within a finite frequency window
vertical bar omega vertical bar << Delta around the Fermi energy the
electronic self-energy has the conventional Fermi-liquid form. With
increasing separation between Fermi level and vHs the spectral
anomalies gradually disappear. (c) 2005 Elsevier Ltd. All rights
reserved.