Finite-size Spin-wave Theory of a Collienar Antiferromagnet
نویسندگان
چکیده
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 spinwave 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 spinwave 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.
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