Abstract
Inelastic neutron scattering measurements of magnetic excitations in hole-doped high- cuprates ( and 0.075) have been performed over a wide temperature range of 5–500 K extending beyond the pseudogap temperature of K for . For , the two-dimensional spin-wave excitations at low temperatures are thermally robust and the dispersion is slightly softened on heating up to K. For , the spin-wave-like excitations in the upper part of the hourglass-shaped dispersion remain at K. However, further heating above K induces a broad ridge centered at ; thereby the hourglass-shaped dispersion becomes blurred above the pseudogap temperature. The localized spin nature of magnetic excitations below suggests that the pseudogap is related to the proximity to a Mott insulator rather than being a precursor of Cooper pairs.
- Received 26 May 2016
- Revised 15 December 2016
DOI:https://doi.org/10.1103/PhysRevB.95.024504
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