Recently, inelastic neutron scattering (INS) experiments on the insulating parent compounds of high-T_c materials were analyzed to extract the value of the superexchange constant J. Starting point of the analysis was the nearest-neighbor Heisenberg model. Motivated by recent ARPES experiments, we consider the effects of a next-nearest neighbor hopping, t′ in the strong coupling limit of the spin-density wave formalism, where it leads to an antiferromagnetic exchange J′>0 between next-nearest neighbor spins. We show that a finite J′ (a) changes the spin-wave velocity and thus the value of J extracted from the INS data, yielding almost identical values for J in La_2CuO_4 and YBa_2Cu_3O_{6.15}, and (b) leads to a considerable change in the high-frequency spin-dynamics. Finally, we calculate the 1/S quantum corrections in the presence of J′ and discuss their relevance for the INS data.
@article{arxiv.cond-mat/9804069,
title = {Effect of next-nearest neighbor hopping on the spin dynamics in antiferromagnets},
author = {Dirk. K. Morr},
journal= {arXiv preprint arXiv:cond-mat/9804069},
year = {2009}
}
Comments
4 pages, RevTeX, 3 eps figures embedded in the text; Fig.1 replaced by correct version