EVIDENCE FOR THE VANHOVE SCENARIO IN HIGH-TEMPERATURE SUPERCONDUCTIVITY FROM QUASI-PARTICLE-LIFETIME BROADENING

Calculations of the quasiparticle-lifetime broadening 1/tau, both for idealized and realistic models of the band structure, show a large lifetime broadening from electron-electron scattering, with the characteristic linear dependence on energy from the Fermi energy seen in high-temperature superconductors, provided that the Fermi level lies near the van Hove singularity in the quasi-two-dimensional band structure. The effect comes from intra-van Hove-singularity scattering without the intervention of nesting.