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Bibliographic Details
Main Authors: Ishii, Kenji, Tsutsui, Kenji, Kawamata, Takayuki, Koike, Yoji
Format: Preprint
Published: 2025
Subjects:
Online Access:https://arxiv.org/abs/2507.22492
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Table of Contents:
  • We report a Cu $K$-edge resonant inelastic x-ray scattering (RIXS) study of spin excitations in the $S$=1/2 antiferromagnetic chain system Sr$_2$CuO$_3$. The spectral weight observed below the charge-transfer gap appears in two-spinon continuum, indicating the fractionalization of a spin-conserving ($ΔS = 0$) magnetic excitation into two-spinon states. The intensity of these excitations reaches a maximum near the midpoint between the center and the boundary of the Brillouin zone, and decreases toward the zone boundary; this behavior contrasts with that of the spin-flip ($ΔS = 1$) excitations typically observed via inelastic neutron scattering or Cu $L_3$-edge RIXS. The momentum dependence of the intensity is described by the spin-exchange dynamical structure factor. A phenomenological analysis of the symmetry between the polarization and the $d$ orbital explains the resonance condition for the two-spinon excitations.