科研之友
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摘要
Inelastic neutron scattering measurements of magnetic excitations in hole-doped high-T-c cuprates La2-xSrxCuO4 (x = 0 and 0.075) have been performed over a wide temperature range of 5-500 K extending beyond the pseudogap temperature of similar to 360 K for x = 0.075. For x = 0, the two-dimensional spin-wave excitations at low temperatures are thermally robust and the dispersion is slightly softened on heating up to T = 400 K. For x = 0.075, the spin-wave-like excitations in the upper part of the hourglass-shaped dispersion remain at T = 300 K. However, further heating above T = 400 K induces a broad ridge centered at (1/2,1/2); thereby the hourglass-shaped dispersion becomes blurred above the pseudogap temperature. The localized spin nature of magnetic excitations below T* suggests that the pseudogap is related to the proximity to a Mott insulator rather than being a precursor of Cooper pairs.
- 出版日期2017-1-9
