Max Planck Institute for Solid State Research, D-70569 Stuttgart, Germany.
Phys Rev Lett. 2012 Jun 1;108(22):227003. doi: 10.1103/PhysRevLett.108.227003. Epub 2012 May 31.
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.
我们使用电子拉曼散射来研究模型单层铜酸盐超导体 HgBa(2)CuO(4+δ)。在过掺杂样品中，我们观察到在冷却到超导转变温度 T(c)以下时，与绝缘铜酸盐中二激子激发相关的高能峰的显著幅度增强。这种效应伴随着超导能隙的出现和拉曼光谱中能隙上方的配对峰，它可以被理解为由于库珀配对相互作用对高能磁涨落的一种迄今未被发现的反馈效应。这意味着高能磁涨落直接参与了配对机制。所有这些效应在两个欠掺杂样品中已经在 T(c)以上发生，这表明与赝能隙相关的存在一个类似的反馈机制。
