Dynamical CPA theory of magnetism - harmonic approximation

• Published in: Physica Status Solidi (b) Vol. 236; no. 2; pp. 498 - 501
• Main Author: Kakehashi, Y.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Berlin WILEY-VCH Verlag 01-03-2003; WILEY‐VCH Verlag; Wiley
• Subjects: 71.10.-w; 75.10.Lp; 75.50.Bb; 75.50.Cc; Band and itinerant models; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Electron states; Exact sciences and technology; General theory and models of magnetic ordering; Lattice fermion models (Hubbard model, etc.); Magnetic properties and materials; Other ferromagnetic metals and alloys; Physics; Plane-wave methods (including augmented plane-wave method); Studies of specific magnetic materials; Theories and models of many electron systems; Perturbation theory; Inorganic compounds; Digital simulation; Curie-Weiss law; Theoretical study; Iron; Electronic density of states; Coulomb interaction; Integral method; BCC lattices; Strong correlation; Transition elements; CPA calculations; Magnetism; Nickel; Dynamic model; Satellite lines
• ISSN: 0370-1972; 1521-3951
• DOI: 10.1002/pssb.200301713

We have developed the dynamical coherent potential approximation (CPA) to the correlated electron system on the basis of the functional integral method and the harmonic approximation. The theory becomes exact in the high temperature limit, reproduces the results of the second order perturbation theory for small Coulomb interaction, and takes into account the terms to describe the strong correlation limit. The numerical calculations show that the theory describes the Curie–Weiss susceptibility, a large reduction of the Curie temperature due to the dynamical effects, and a many‐body satellite peak as well as a band narrowing in the density of states.