Abstract
We probe the collective magnetic modes of and underdoped (LSCO) by momentum resolved resonant inelastic x-ray scattering (RIXS) at the Cu edge. For the undoped antiferromagnetic sample, we show that the single magnon dispersion measured with RIXS coincides with the one determined by inelastic neutron scattering, thus demonstrating that x rays are an alternative to neutrons in this field. In the spin dynamics of LSCO, we find a branch dispersing up to coexisting with one at lower energy. The high-energy branch has never been seen before. It indicates that underdoped LSCO is in a dynamic inhomogeneous spin state.
- Received 29 October 2009
DOI:https://doi.org/10.1103/PhysRevLett.104.077002
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