# Bilder aus der Forschung des PGI-1/IAS-1

Renormalized spin susceptibility for nickel
Imaginary part of the renormalized spin susceptibility for fcc Ni as a function of momentum and frequency, obtained from a series of first-principles Bethe-Salpeter calculations. The quadratic spin-wave dispersion is clearly visible. The high resolution of the picture reveals strong mixing of collective and single-particle (Stoner) excitations, which can lead to energy gaps in the spin-wave branch (see inset).