| Автор | Yu A Izyumov |
| Автор | B M Letfulov |
| Автор | E V Shipitsyn |
| Дата выпуска | 1992-12-07 |
| dc.description | The Hubbard model in the limit of strong Coulomb interaction (the (t-J) model) is studied by the diagram technique for Hubbard operators. The generalized random-phase approximation (GRPA) is formulated as an approximation taking into account electron loop-type diagrams. Within the framework of this approximation, both the dynamic magnetic and dielectric susceptibilities are calculated for a wide interval of electron concentrations, 0<n<1. The magnetic susceptibility shows a crossover in the magnetic behaviour of the system from pure itinerant magnetism to magnetism with localized magnetic moments. The crossover occurs at a critical point, n<sub>c</sub>, when the chemical potential for electrons of the lower Hubbard band changes sign. Magnetic phase diagrams are constructed on the (t/U, n) plane at T=0 for different types of crystal lattices. The behaviour of magnetic phases with temperature is also studied. The GRPA leads to a too drastic crossover, especially at low temperatures, because of insufficient allowance for the charge and spin fluctuations on a site. Summation of special diagram series shows that the Gaussian fluctuations of the effective electric and magnetic fields lead to a smoother picture of the crossover. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Generalized random-phase approximation in the theory of strongly correlated systems |
| Тип | paper |
| DOI | 10.1088/0953-8984/4/49/023 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 4 |
| Первая страница | 9955 |
| Последняя страница | 9970 |
| Аффилиация | Yu A Izyumov; Inst. of Metal Phys., Russian Acad. of Sci., Russia |
| Аффилиация | B M Letfulov; Inst. of Metal Phys., Russian Acad. of Sci., Russia |
| Аффилиация | E V Shipitsyn; Inst. of Metal Phys., Russian Acad. of Sci., Russia |
| Выпуск | 49 |
