Anisotropic transport in the overdoped High-Tc superconductors within the Van Hove scenario

Abstract

Recent Raman experiments [F. Venturini et al., Phys. Rev. Lett. {\bf 89}, 107003-1,(2002)] done in $B{i}_{2}S{r}_{2}CaC{u}_2{O}_4$ have found that antinodal quasiparticles become insulating when the doping is varied from overdoped to optimally doped while nodal quasiparticles remain metallic. We propose a simple explanation based on the incoherence of the spectral function in the antinodal direction due to the strong scattering suffered by the quasiparticles in the proximity of the Van Hove singularity.

3 pages, 1 figure