Calculation of the four-spin cyclic exchange in cuprates
arXiv:1807.05545 · doi:10.1103/PhysRevB.98.125118
Abstract
Starting from the three-band Hubbard model for the cuprates, we calculate analytically the four-spin cyclic exchange in the limit of infinite on-site Coulomb repulsion and zero O-O hopping using two methods: i) perturbation theory in , where is the Cu-O hopping and the Cu-O charge transfer energy and ii) exact solution of a CuO plaquette. The latter method coincides with the first to order eight in and permits to extend the results to of order one. The results are relevant to recent experimental and theoretical research that relate the splitting of certain spin excitations with and the superconducting critical temperature.
6 pages, 2 figures, some typos corrected and references added