2003/04/03 by A. Uldry, Anne‐Christine Uldry, R. J. Elliott
Physics and Astronomy · #Advanced Condensed Matter Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #cond-mat.str-el
paper · pdf · doi:10.1088/0953-8984/17/19/007
published as J. Phys.: Condens. Matter 17 (2005) 2903-2917
arxiv created 2003/04/03 · openalex publication_date 2005/04/29 · arxiv updated 2009/11/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
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.