In-plane superfluid density and microwave conductivity of the organic   superconductor \kappa-(BEDT-TTF)2Cu[N(CN)2]Br: evidence for d-wave pairing   and resilient quasiparticles
  We report the in-plane microwave surface impedance of a high quality single crystal of \kappa-(BEDT-TTF)2Cu[N(CN)2]Br. In the superconducting state, we find three independent signatures of d-wave pairing: i) a strong, linear temperature dependence of superfluid density; ii) deep in the superconducting state the quasiparticle scattering rate \Gamma ~ T^3; and iii) no BCS coherence peak is observed in the quasiparticle conductivity. Above T_c, the Kadowaki-Woods ratio and the temperature dependence of the in-plane conductivity show that the normal state is a Fermi liquid below ~ 23 K, yet resilient quasiparticles dominate the transport up to ~ 50 K. 
S. Milbradt, A. A. Bardin, C. J. S. Truncik, W. A. Huttema, A. C.   Jacko, P. L. Burn, S.-C. Lo, B. J. Powell, and D. M. Broun
cond-mat.supr-con cond-mat.str-el