Generalized spin susceptibility in the correlated narrow-energy-band model

Abstract

An approximate expression has been derived for the wave number and frequency-dependent spin susceptibility χ(Q, ω) of the paramagnetic phase of a system of interacting electrons in a narrow s band. This expression has the property of reducing to the random phase result in the weak-interaction (band) limit and gives a Curie law for the ordinary susceptibility in the strong-interaction (atomic) limit. When the number of electrons per atom is small, χ(Q, ω) is expressible in terms of an effective electron-electron interaction similar to that of Kanamori. The stability of the paramagnetic phase relative to ferromagnetic ordering is discussed.