2010/04/30 by M. Guarise, B. Dalla Piazza, M. Moretti Sala +13 · 1 citation
Physics and Astronomy · #cond-mat.str-el #cond-mat.supr-con
paper · pdf · doi:10.1103/physrevlett.105.157006
published as Phys. Rev. Lett. 105, 157006 (2010) · 4 pages, 4 figures
arxiv created 2010/09/06 · arxiv updated 2014/08/05
Using high-resolution resonant inelastic x-ray scattering (RIXS), we performed a momentum-resolved study of magnetic excitations in the model spin-1/2 2D antiferromagnetic insulator Sr2CuCl2O2. We identify both a single-spin-wave feature and a multi-magnon continuum, and show that the X-ray polarization can be used to distinguish these two contributions in the cross-section. The spin-waves display a large (70 meV) dispersion between the zone-boundary points (π,0) and (π/2,π/2). Employing an extended t-t'-t"-U one-band Hubbard model, we find significant electronic hopping beyond nearest-neighbor Cu ions. We conclude that sizeable extended magnetic interactions are present in \scoc and probably important in all undoped cuprates.