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Single-Siet Spin Fluctuation Theory of Itinerant-Electron Systems with Narrow Bands

1980; Physical Society of Japan; Volume: 49; Issue: 1 Linguagem: Inglês

10.1143/jpsj.49.178

1347-4073

Hideo Hasegawa,

Theoretical and Computational Physics

The spin fluctuation theory of itinerant-electron magnetism is developed by using the static functional integral method combined with the single-site alloy analogy approximation. The theory is shown to provide an interpolating description of itinerant electron magnetism yielding good results in some important limits; in the weak interaction limit or T =0 K it reduces to the Hartree-Fock theory, and in the strong coupling limit for the half-filled band it reproduces the results of the molecular-field theory. With the use of the half-filled Bell shape band the temperature dependences of the average moment, the local moment, the susceptibility and the specific heat are calculated numerically for various values of the electron-electron interaction.