title: Feedback effect on high-energy magnetic fluctuations in the model high-temperature superconductor HgBa2CuO(4+δ) observed by electronic Raman scattering.
abstract: We use electronic Raman scattering to study the model single-layer cuprate superconductor HgBa(2)CuO(4+δ). In an overdoped sample, we observe a pronounced amplitude enhancement of a high-energy peak related to two-magnon excitations in insulating cuprates upon cooling below the critical temperature T(c). This effect is accompanied by the appearance of the superconducting gap and a pairing peak above the gap in the Raman spectrum, and it can be understood as a hitherto-undetected feedback effect on the high-energy magnetic fluctuations due to the Cooper pairing interaction. This implies a direct involvement of the high-energy magnetic fluctuations in the pairing mechanism. All of these effects occur already above T(c) in two underdoped samples, demonstrating a related feedback mechanism associated with the pseudogap.
authors.affiliation: Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany. yuan.li@pku.edu.cn
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.forename: M
authors.initials: M
authors.lastname: Le Tacon
authors.forename: M
authors.initials: M
authors.lastname: Bakr
authors.forename: D
authors.initials: D
authors.lastname: Terrade
authors.forename: D
authors.initials: D
authors.lastname: Manske
authors.forename: R
authors.initials: R
authors.lastname: Hackl
authors.forename: L
authors.initials: L
authors.lastname: Ji
authors.forename: M K
authors.initials: MK
authors.lastname: Chan
authors.forename: N
authors.initials: N
authors.lastname: Barišić
authors.forename: X
authors.initials: X
authors.lastname: Zhao
authors.forename: M
authors.initials: M
authors.lastname: Greven
authors.forename: B
authors.initials: B
authors.lastname: Keimer