Shifting of the magnetic-resonance peak to lower energy in the superconducting state of underdoped YBa<sub>2</sub>Cu<sub>3</sub>O<sub>6.8</sub>
P. Bourges; L. P. Regnault; Y. Sidis; J. Bossy; P. Burlet; C. Vettier; J. Y. Henry; M. Couach
Журнал:
EPL (Europhysics Letters)
Дата:
1997-05-01
Аннотация:
Inelastic neutron scattering has been used to determine the dynamic spin fluctuations in an underdoped high-temperature superconductor YBCO<sub>6.8</sub> single crystal. The magnetic resonance, that occurs around 40 meV in overdoped samples, is shifted to a lower energy, E<sub>r</sub> = 34 meV. A constant ratio, E<sub>r</sub>/k<sub>B</sub>T<sub>C</sub> = 4.9 ± 0.2, almost independent of the doping level, is found. According to numerous theoretical approaches, this finding supports the idea that the resonance energy is proportional (approximately twice) to the superconducting gap.
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