Relaxation time of the order parameter in a high-temperature superconductor

Abstract

We present femtosecond time-resolved measurements on the high-${\mathit{T}}_{\mathit{c}}$ superconductor ${\mathrm{Tl}}_{2}$${\mathrm{Ba}}_{2}$${\mathrm{Ca}}_{2}$${\mathrm{Cu}}_{3}$${\mathrm{O}}_{10}$. At temperatures below ${\mathit{T}}_{\mathit{c}}$, we observe a relaxation process which is distinct from the equilibration of hot carriers in the normal state. Our results demonstrate an increasing relaxation rate as the superconducting gap opens. This is consistent with the behavior of conventional metallic superconductors.