Сибирский федеральный университет

Тип публикации: статья из журнала

Год издания: 1998

Идентификатор DOI: 10.1134/1.558607

Аннотация: We discuss, in connection with the problem of the ground state in the Hubbard model with U = infinity, the normal (nonmagnetic) N-state of a system over the entire range of electron concentrations n less than or equal to 1. It is found that in a one-particle approximation, e. g., in the generalized Hartree-Fock approximation, the energy epsilon(0)(n) of the N-state is lower than the energy epsilon(FM)(n) of a saturated ferromagnetic state for all values of n. Using the random phase approximation we calculate the dynamical magnetic susceptibility and show that the N-state is stable for all values of n. A formally exact representation is derived for the mass operator of the one-particle electron Green's function, and its expression in the self-consistent Born approximation is obtained. We discuss the first Born approximation and show that when correlations are taken into account, the attenuation vanishes on the Fermi surface and the electron distribution function at T = 0 acquires a Migdal discontinuity, whose magnitude depends on n. The energy of the N-state in this approximation is still lower than epsilon(FM)(n) for n

Журнал: JOURNAL OF EXPERIMENTAL AND THEORETICAL PHYSICS

Выпуск журнала: Vol. 87, Is. 6

Номера страниц: 1159-1166

ISSN журнала: 10637761

Место издания: WOODBURY

Издатель: AMER INST PHYSICS

• Kuz'min E.V. (Krasnoyarsk State University)
• Baklanov I.O. (L. V. Kirenskii Institute of Physics,Siberian Branch,Russian Academy of Sciences)

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