| Автор | A F Barabanov |
| Автор | L A Maksimov |
| Автор | O A Starykh |
| Автор | G V Uimin |
| Дата выпуска | 1990-11-12 |
| dc.description | The authors investigate the properties of the two-dimensional quantum S=1/2 Heisenberg antiferromagnetic model on a square lattice by means of a block approach. The lattice is divided into four spin square blocks and the Hamiltonian is expressed in terms of low-energy block states. In the framework of the mean-field theory based on the 'auxiliary-boson' formalism; they show that the spin excitation spectrum contains one singlet mode with the temperature-dependent gap and three degenerate triplet modes. The asymptotic low-temperature spin-spin correlations are proportional to R<sup>-3/2</sup> exp(-R(1/ xi <sub>1</sub>+1/ xi <sub>2</sub>)), where xi <sub>1</sub>=exp(A/T), xi <sub>2</sub>=constant and A approximately=0.5J. The uniform susceptibility tends to zero in agreement with numerical results; the energy per site is close to -0.57J. Beyond the meanfield theory the authors find gapless collective excitations analogous to the gapless mode in the neutral Fermi gas with attraction. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | Spin excitations in the S=1/2 Heisenberg antiferromagnetic model on a square lattice |
| Тип | paper |
| DOI | 10.1088/0953-8984/2/45/006 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 2 |
| Первая страница | 8925 |
| Последняя страница | 8933 |
| Аффилиация | A F Barabanov; Vereschagin Inst. for High Pressure Phys., Moscow, USSR |
| Аффилиация | L A Maksimov; Vereschagin Inst. for High Pressure Phys., Moscow, USSR |
| Аффилиация | O A Starykh; Vereschagin Inst. for High Pressure Phys., Moscow, USSR |
| Аффилиация | G V Uimin; Vereschagin Inst. for High Pressure Phys., Moscow, USSR |
| Выпуск | 45 |
