Abrupt transition in quasiparticle dynamics at optimal doping in a cuprate superconductor system

TL;DR

This study reveals an abrupt change in quasiparticle dynamics at optimal doping in a cuprate superconductor, indicating a sharp transition in electronic behavior associated with maximum superconducting transition temperature.

Contribution

It provides the first direct time-resolved evidence of a sudden transition in quasiparticle decay dynamics at optimal doping in cuprates.

Findings

Quasiparticle decay kinetics change abruptly at optimal doping.

Sign of reflectivity change Delta R shifts at optimal doping.

Transition temperature Tc is maximized at this doping level.

Abstract

We report time-resolved measurements of the photoinduced change in reflectivity, Delta R, in the Bi2Sr2Ca(1-y)Dy(y)Cu2O(8+delta) (BSCCO) system of cuprate superconductors as a function of hole concentration. We find that the kinetics of quasiparticle decay and the sign of Delta R both change abruptly where the superconducting transition temperature Tc is maximal. These coincident changes suggest that a sharp transition in quasiparticle dynamics takes place precisely at optimal doping in the BSCCO system.