Nonequilibrium superconductivity in Y1−xPrxBa2Cu3O7 thin films
Abstract We have measured the picosecond conductivity dynamics in Y1−xPrxBa2Cu3O7 thin films from 0.3– 2.0 THz . Our experimental technique measures the complex conductivity σre(ω)+iσim(ω) permitting the simultaneous observation of superconducting pair and quasiparticle dynamics. We emphasize aspects of the conductivity dynamics which extend our previous results (Phys. Rev. B 63 (2001) 140502(R)). In particular, the recovery of σre is faster than σim, and the recovery of σim decreases with increasing frequency. This suggests another carrier relaxation pathway, in addition to superconducting pair recovery, following optical excitation.