High-Temperature Magnetic Susceptibility of Interacting Electrons in a Solid. II

A new alternative expression for the third virial coefficient for fermions is derived. It is used to deduce an expression for the high-temperature magnetic susceptibility of electrons which interact according to the Hubbard Hamiltonian. The work extends a previous calculation which considered only the second virial coefficient. The results are compared with the Stoner theory of the ferromagnetism of itinerant electrons. The inclusion of the third virial coefficient modifies the usual expression for the susceptibility and indicates an increased tendency toward ferromagnetism.