We consider the square lattice Heisenberg antiferromagnet with plaquette ring exchange and a finite interlayer coupling leading to a consistent description of the spin-wave excitation spectrum in La2CuO4. The values of the in-plane exchange parameters, including ring exchange J□, are obtained consistently by an accurate fit to the experimentally observed in-plane spin-wave dispersion, while the out-of-plane exchange interaction is found from the temperature dependence of the sublattice magnetization at low temperatures. The fitted exchange interactions J = 151.9 meV and J□ = 0.24J give values for the spin stiffness and the Néel temperature in excellent agreement with the experimental data.
|Number of pages||4|
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 1 Sep 2002|