Two-component dynamics of the order parameter of high temperature Bi2Sr2CaCu2O8+delta superconductors revealed by time-resolved Raman scattering

Phys Rev Lett. 2009 May 1;102(17):177004. doi: 10.1103/PhysRevLett.102.177004. Epub 2009 Apr 29.

Abstract

We study the dynamics of the superconducting order parameter in the high-Tc cuprate Bi2Sr2CaCu2O8+delta by employing a novel time-resolved pump-probe Raman experiment. We find two different coupling mechanisms that contribute equally to the pair-breaking peak. One coupling sets in very fast at 2 ps and relaxes slowly, while the other one is delayed and sets in roughly at 5 ps and relaxes fast. A model that couples holes through phonons is able to reproduce one part of the condensate dynamics; thus, we argue that hole-spin interactions are of importance as well.