Renormalization of spectral line shape and dispersion below Tc in Bi2Sr2CaCu2O8+δ

Abstract

Angle-resolved photoemission data in the superconducting state of Bi2Sr2CaCu2O8+δ show a kink in the dispersion along the zone diagonal, which is related via a Kramers-Krönig analysis to a drop in the low energy scattering rate. As one moves towards (π, 0), this kink evolves into a spectral dip. The occurrence of these anomalies in the dispersion and line shape throughout the zone indicates the presence of a new energy scale in the superconducting state. © 2001 The American Physical Society.