Renormalization group approach to the normal state of copper-oxide superconductors

We study by means of renormalization group techniques the effect that the van Hove singularities observed experimentally in the copper-oxide superconductors may have on the two-dimensional electron liquid. We find significant deviations from Fermi liquid behavior that lead to the appearance of an unstable fixed point in the renormalization group Bow of the effective coupling constant. Besides the attenuation of electron quasiparticles already known on phenomenological grounds, our approach is able to explain the reduction in the dispersion of the band as well as the pinning of the Fermi level near the singularity, as observed in the photoemission experiments.