Susceptibility scaling and vertex corrections for a nested Fermi liquid

An unusual scaling of the spin susceptibility, as a function of frequency/t emperature, was discovered for noninteracting electrons on a nested Fermi s urface. This scaling has been confirmed by neutron-scattering experiments o n high-temperature superconductors, and it can explain the anomalous quasip article damping in cuprates if electron collisions are dominant. The presen t work proves that self-energy and vertex corrections preserve the scaling features of the susceptibility to leading order in the Hubbard on-site Coul omb repulsion U. Analytic results for the static susceptibility show how se lf-energy and vertex terms modify the traditional random-phase approximatio n results for a spin-density-wave instability and suppress the charge susce ptibility. These results are relevant to d-wave superconductors, organic me tals, and chromium. [S0163-1829(99)02402-9].