Anisotropic ultrafast dynamics in doped Y1-xCaxBa2Cu3O7-delta superconducting thin films

Abstract

The anisotropic dynamics of photoinduced quasiparticle in the Y1-xCaxBa2Cu3O7-delta (YCBCO) is revealed by using the orientation-resolved femtosecond reflection spectroscopy. This bulk-sensitive spectroscopy, combining with the well-textured (110)- and (100)- YCBCO thin films, serves as an effective probe to quasiparticle relaxation dynamics along different crystallographic orientations. Since the temperature at which the peak of temperature-dependent relaxation time (tau) manifested in the transient reflectance (Delta R/R) measurements is believed to intimately relate to the opening of superconducting gap, the results reported here should shed some light on the issue of the competing order scenarios for over-doped high-T-c superconductors.