Fermi liquid interactions and relaxation rate of thermal quasiparticles in a d-wave superconductor

P. J. Hirschfeld, P. C. Howell

Xu-Cheng Wang, Xiao Yan Xu, Yang Qi

VICTOR A. KHODEL, MIKHAIL V. ZVEREV

Mohammad Ali Shahzamanian

The relaxation rates of thermal and hot quasiparticles when scatter with each other are calculated. The transition probabilities at low temperatures express in terms of Bogoliubov coefficients, singlet and triplet scattering amplitudes and dimensionless Landau parameters. Comparison of the theoretical and experimental results gives the values of two Landaus parameters .

Michael F. Smith, P. Pairor

The relaxation of a $d$-wave superconductor that has been driven out of equilibrium by an optical pulse is investigated. We consider a simple model for the low-energy nonequilibrium state, one in which the unpaired quasiparticles form Fermi spheres near the gap nodes, and calculate the decay rate of the quasiparticle population due to phonon-assisted recombination. In the high density limit for the photoinjected quasiparticles, the decay rate $dn∕dt$ is found to vary as ${n}^{5∕2}$, which differs from the ${n}^{2}$ form commonly adopted in phenomenological models of the relaxation dynamics. In the low density limit, the decay is exponential. From numerical estimates, we determine that phonon-assisted recombination could play an important role over the picosecond time scales of current interest. We compare our results to pump-probe optical experiments on high ${T}_{C}$ cuprates and find reasonable agreement for the decay rate in underdoped YBCO for low laser intensity.

Steven H. Simon, Patrick A. Lee