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

TL;DR

This paper explains the anisotropic transport behavior in overdoped high-Tc superconductors by linking quasiparticle incoherence near Van Hove singularities to experimental Raman observations.

Contribution

It introduces a simple model attributing antinodal quasiparticle incoherence to strong scattering near Van Hove points, explaining experimental anisotropic transport.

Findings

Antinodal quasiparticles become insulating near optimal doping.

Nodal quasiparticles remain metallic across doping levels.

Spectral function incoherence is linked to Van Hove singularities.

Abstract

Recent Raman experiments [F. Venturini et al., Phys. Rev. Lett. {\bf 89}, 107003-1,(2002)] done in $Bi_2 Sr_2 Ca Cu_2 O_4$ 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.