Zn-substitution effects on the low-energy quasiparticles in Bi 2Sr 2CaCu 2O 8+ δ studied by angle-resolved photoemission spectroscopy

Abstract

We have performed high-resolution angle-resolved photoemission spectroscopy on Bi 2Sr 2Ca(Cu 1− x Zn x ) 2O 8+ δ ( x=0.0, 0.05) to study the Zn-substitution effects on the low-energy quasiparticles. We found that the Zn substitution causes the reduction of the quasiparticle intensity and the superconducting gap, while it does not affect the normal-state band dispersion, the Fermi surface, or the quasiparticle lifetime. This indicates that the Zn substitution locally destroys or hinders the superconducting pairing and as a result decreases the superfluid density, but does not affect the long-range coherence among quasiparticles.