2015/03/25 by Jun-ichi Igarashi, Tatsuya Nagao · 1 citation
Physics and Astronomy · #Anisotropy #Cuprate #Excitation #Ground state #Inelastic scattering #Isotropy #Physics of Superconductivity and Magnetism #Quantum Chromodynamics and Particle Interactions #Resonant inelastic X-ray scattering #Scattering #Symmetry breaking #X-ray Spectroscopy and Fluorescence Analysis #cond-mat.str-el
paper · pdf · doi:10.1088/0953-8984/27/18/186002
published as J. Phys.:Condens. Matter, vol. 27, 186002 (2015) · Latex, 13 pages, 9 figures, to be published in Journal of Physics:Condensed Matter
arxiv created 2015/03/25 · openalex publication_date 2015/04/20 · arxiv updated 2015/06/24 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We study the magnetic excitation spectra of resonant inelastic x-ray scattering (RIXS) at the L-edge from undoped cuprates beyond the fast collision approximation. We analyse the effect of the symmetry breaking ground state on the RIXS process of the Heisenberg model by using a projection procedure. We derive the expressions of the scattering amplitude in both one-magnon and two-magnon excitation channels. Each of them consists of the isotropic and anisotropic contributions. The latter is a new finding and attributed to the long range order of the ground state. The presence of anisotropic terms is supported by numerical calculations on a two-dimensional spin cluster. We express the RIXS spectra in the form of spin-correlation functions with the coefficients evaluated on the cluster, and calculate the function in a two dimensional system within the 1/S expansion. Due to the anisotropic terms, the spectral intensities are considerably enhanced around momentum transfer q = 0 in both one-magnon and two-magnon excitation channels. This finding may be experimentally confirmed by examining carefully the q-dependence of the spectra.