Photoinduced changes of reflectivity in single crystals of YBa2Cu3O6.5 (ortho II)

Phys Rev Lett. 2002 Apr 1;88(13):137001. doi: 10.1103/PhysRevLett.88.137001. Epub 2002 Mar 14.


We report measurements of the photoinduced change in reflectivity of an untwinned single crystal of YBa2Cu3O6.5 in the ortho II structure. The decay rate of the transient change in reflectivity is found to decrease rapidly with decreasing temperature and, below T(c), with decreasing laser intensity. We interpret the decay as a process of thermalization of antinodal quasiparticles, with a rate determined by inelastic scattering of quasiparticle pairs.