Feromagnetism in the single-band Hubbard model in the limit of strong correlations

Kenn Kubo

Kenn Kubo, Masahito Tada

K. Kubo, M. Tada

The high temperature series of the susceptibility of the single-band Hubbard model in the strong correlation limit is analyzed by the use of the Padé method. The appearance of the Curie temperature is observed for fcc lattice in a nearly half-filled region. The convergence is still not sufficient to derive a reliable conclusion. The specific heat is also studied.

Katsunori Kubo, Masahito Tada

The high temperature series of the thermodynamic potential and the uniform susceptibility have been investigated for the single-band Hubbard model in the strong correlation limit. It is rigorously shown that the series absolutely converge both in the low density and the half-filled limit. Correct first terms have been obtained up to the ninth order in terms of the inverse temperature. Coefficients of the series are oscillating rapidly as functions of the occupation probability of electrons.

Andrzej M. Oleś, Józef Spałek

T. Herrmann, Wolfgang Nolting