Аналітичний метод для дослідження антиферомагнітного впорядкування в моделі мотт-габбардівського матеріалу

Abstract

In this work the indirect interactions in narrow-band material connected with both the charge transfer and licalized magnetic moment exchange has been analised within the effectiwe Hamiltonain approach. Using new projection procedure for Green function method a system of equations for chemical potential and magnetization has been obtained. On this base, Neel temperature for narrow-band antiferromagnet has been calculated. It has been shown that for realistic model energy parameters, antiferromagnetic order disappears even for low values of holes concentration, thus doping of Mott-Hubbard insulator destabilizes antiferromagnetism. It allows us to interpret concentrational dependence of Neel temperature observed in narrow band materials.