Energy-Dependent Enhancement of the Electron-Coupling Spectrum of the Underdoped Bi2Sr2CaCu2O8+d Superconductor

Abstract

We have determined the electron-coupling spectrum of superconducting Bi2Sr2CaCu2O8+d from high-resolution angle-resolved photoemission spectra by two deconvolution-free robust methods. As hole concentration decreases, the coupling spectral weight at low energies ~<15 meV shows a twofold and nearly band-independent enhancement, while that around ~65 meV increases moderately, and that in ~>130 meV decreases leading to a crossover of dominant coupling excitation between them. Our results suggest the competition among multiple screening effects, and provide important clues to the source of sufficiently strong low-energy coupling, λLE ~ 1, in underdoped system.

References in corpus (5)

• Unified electronic phase diagram for hole-doped high-Tc cuprates
• Growth, characterization and physical properties of high-quality large single crystals of Bi${}_2$Sr${}_{2-x}$La${}_x$CuO${}_6$ high-temperature superconductors
• Rapid change of electronic anisotropy in overdoped (Y,Ca)Ba2Cu3O7-d
• Universal optimal hole-doping concentration in single-layer high-temperature cuprate superconductors
• Intrinsic electronic superconducting phases at 60 K and 90 K in double-layer YBa${}_2$Cu${}_3$O${}_{6+\delta }$