Finite-Size Spin-Wave Theory of a Collinear Antiferromagnet
Abstract
The ground-state and low-energy properties of the two-dimensional J1-J2 Heisenberg model in the collinear phase are investigated using finite-size spin-wave theory [Q. F. Zhong and S. Sorella, Europhys. Lett. 21, 629 (1993)], and Lanczos exact diagonalizations. For spin one-half — where the effects of quantization are the strongest — the spin-wave expansion turns out to be quantitatively accurate for J2/J1≳0.8. In this regime, both the magnetic structure factor and the spin susceptibility are very close to the spin-wave predictions. The spin-wave estimate of the order parameter in the collinear phase, m†≃0.3, is in remarkable agreement with recent neutron scattering measurements on Li2VOSiO4.
- Publication:
-
International Journal of Modern Physics B
- Pub Date:
- 2003
- DOI:
- 10.1142/S0217979203023148
- arXiv:
- arXiv:cond-mat/0306679
- Bibcode:
- 2003IJMPB..17.4819C
- Keywords:
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- Quantum antiferromagnets;
- spin-wave theory;
- exact diagonalizations;
- Condensed Matter - Strongly Correlated Electrons
- E-Print:
- 10 pages, 3 figures