We examine two-spin (2S) and cyclic four-spin (4S) magnetic interactions in insulating ladder and two-dimensional (2D) cuprates. By a comparison of eigenstates between d-p and Heisenberg models, we evaluate magnitudes of these interactions. We find that the 4S interaction is ∼10% of nearest neighboring 2S interaction, and a diagonal 2S interaction is considerably small. The 4S interaction for a ladder cuprate is larger than that for 2D one, and plays an important role in the low-energy excitation. The Heisenberg ladder with the obtained 2S and 4S interactions reproduces very well the experimental result of the temperature dependence of the magnetic susceptibility.
Cite
@article{arxiv.cond-mat/9906444,
title = {Magnetic Interaction in Insulating Cuprates},
author = {Yoshiaki Mizuno and Takami Tohyama and Sadamichi Maekawa},
journal= {arXiv preprint arXiv:cond-mat/9906444},
year = {2007}
}