Spectral characteristics of the antiferromagnetic spin-1/2 Heisenberg model on the square lattice in a magnetic field
| Autor: | Savchenkov, P. S., Barabanov, A. F. |
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| Rok vydání: | 2020 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1016/j.jmmm.2020.167505 |
| Popis: | We predict that spin-waves in an ordered square quantum antiferromagnet in a transverse magnetic field (h) may demonstrate three modes of spin excitations. Starting from the self-consistent rotation-invariant Green's function method, a new mean-field theory is constructed for h not equal to 0. The method preserves the translational and the axial symmetries, and provides exact fulfillment of the single-site constraint for each of the three modes. We examine the dynamical structure factors S(aa)(k,w), a= x, y, z. It is shown, that the introduction of h leads to the hybridization of two degenerate spin modes due to the appearance of a nondiagonal on a, b spin-spin Green's functions. The comparison of the theory with the exact diagonalization study and with results on inelastic neutron scattering experiments is discussed at T = 0. We discuss also the correspondence of the theory to the existing theories, which allow only two spin excitations modes for the total S(k,w). Comment: 13 pages, 3 figures |
| Databáze: | arXiv |
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