Doping dependence of the electron–phonon and electron–spin fluctuation interactions in the high-Tc superconductor Bi2Sr2CaCu2O8+δ

• Main Authors: Springer, D., Nair, S. K., Zou, X. Q., Cheong, S. A., Panagopoulos, C., Tamegai, T., Eisaki, H., Ishida, S., Uchida, S., Taylor, A. J., Zhu, J. -X., Chia, Elbert E. M.
• Other Authors: School of Physical and Mathematical Sciences
• Format: Article
• Language: English
• Published: 2014
• Subjects: DRNTU::Science::Physics::Optics and light
• Online Access: https://hdl.handle.net/10356/101503; http://hdl.handle.net/10220/24171
• Institution: Nanyang Technological University

Using ultrafast optical techniques, we detect two types of bosons strongly coupled to electrons in the family of Bi2Sr2CaCu2O8+ (Bi-2212) from the underdoped to overdoped regimes. The different doping dependences of the electron–boson coupling strengths enable us to identify them as phonons and spin fluctuations: electron–phonon coupling ( e−ph) peaks at optimal doping, while electron–spin fluctuation coupling ( e−sf) decreases monotonically with doping. This observation is consistent with two facts: (i) superconductivity is in close proximity with antiferromagnetism at low dopings and (ii) a pronounced lattice renormalization effect at larger dopings.