Electron — phonon coupling in underdoped high-temperature superconductors
Cross-Correlated Materials Research Group (CMRG), ASI, RIKEN, Wako, Saitama , Japan
Results indicating the important role of the electron — phonon coupling in high-temperature superconductivity compounds are presented, with emphasis on its implications for angle-resolved photoemission and optical conductivity. The
dimensionless phonon coupling constant λ is determined by comparing the experimental and theoretical results. Although undoped materials are in the strong-coupling (λ ~ 1) regime, hole doping decreases λ, bringing compounds to the intermediate-coupling regime at optimum hole concentrations.