Spin susceptibility divergence in high-temperature superconductors

Abstract

Neutron scattering experiments at low frequency reveal susceptibility peaks in La 2− x Sr x CuO 4 which diverge as the temperature is lowered toward the superconducting transition. This divergence at a nesting momentum stands out from the conventional Pauli susceptibility of this cuprate at long wavelengths. We explain the peak singularity by calculating many-body Coulomb correlations which originate from Fermi surface nesting and dominant vertex corrections. We sum the leading singularities using the parquet method and find that the susceptibility diverges as T − α , where α depends on the Coulomb interaction. Our theory also explains a similar susceptibility surge in the metallic V 2O 3.