Unraveling higher-order corrections in the spin dynamics of RIXS spectra
ORAL
Abstract
Resonant inelastic x-ray scattering (RIXS) is an evolving tool for investigating spin dynamics of strongly correlated materials, which complements inelastic neutron scattering. Both techniques have found that non-spin-conserving (NSC) excitations in quasi-1D isotropic quantum antiferromagnets are confined to the two-spinon phase space. Outside this phase space, only spin-conserving (SC) four-spinon excitations have been detected using O K-edge RIXS. Here, we investigate SrCuO2 and find four-spinon excitations outside the two-spinon phase space at both O K- and Cu L3-edges. Using the Kramers-Heisenberg formalism, we demonstrate that the four-spinon excitations arise from both SC and NSC processes at Cu L3-edge. We show that these new excitations only appear in the second-order terms of the ultra-fast core-hole lifetime expansion and arise from long-range spin fluctuations. These results thus open a new window to the spin dynamics of quantum magnets.
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Publication: U. Kumar, et al., arXiv:2110.03186 (2021)
Presenters
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Umesh Kumar
- Los Alamos National Laboratory