Two-particle propagator and magnetic susceptibility in the Hubbard model- An improved treatment
arXiv:cond-mat/0304083 · doi:10.1088/0953-8984/17/19/007
Abstract
We treat the two-particle Green's function in the Hubbard model using the recently developed tau-CPA, a hybrid treatment that applies the coherent-potential approximation (CPA) up to a time tau related to the inverse of the band width, after which the system is averaged using the virtual-crystal approximation (VCA). This model, with suitable approximations, does predict magnetism for a modified Stoner criterion. The evaluation of the two-particle propagator in the tau-CPA requires the solution of the pure CPA, within whose formalism the vertex correction and the weighted Green's functions are obtained. The dynamical susceptibility, including the vertex correction and the weighted scattering by the residual interaction, is calculated and shows a spin wave spectrum in the ferromagnetic regime.
References in corpus (4)
- Charm electroproduction viewed in the variable-flavour number scheme versus fixed-order perturbation theory
- Ferromagnetism in the Hubbard Model on fcc-type lattices
- Phase diagram and quasiparticle properties of the Hubbard model within cluster two-site DMFT
- Approximation of excitonic absorption in disordered systems using a compositional component weighted CPA