COULOMB INTERACTION AND DISORDER AT Q=2K(F) - A NOVEL INSTABILITY OF THE FERMI SEA AND IMPLICATIONS FOR AMORPHOUS-ALLOYS

We investigate the influence of interference between Coulomb interacti on and impurity scattering on the static electronic response (chi)(0, q) in disordered metals to leading order in the effective Coulomb inte raction. When the transport relaxation time is much shorter than the q uasiparticle lifetime, (chi)(0, q) exhibits a power-law divergence at the Fermi surface (q = 2k(F)), signaling an instability towards charge density oscillations. It causes a phase shift of the Friedel oscillat ions as well as an enhancement of their amplitude. Our results are con sistent with experiments and may be relevant for understanding the sta bility of the amorphous state of certain alloys against crystallizatio n.