THERMAL-CONDUCTIVITY OF ORGANIC SUPERCONDUCTORS

Results of measurements of thermal conductivity kappa(T) and resistivi ty rho(T) of quasi-2-dimensional organic superconductor kappa-(ET)(2)C u[N(CN)(2)]Br with high transition temperature T-c approximate to 11K are presented. Estimations of the electron contribution kappa(e) into the total conductivity kappa(T) have shown the predominance of the lat tice component kappa(p) similar to 10(3) kappa(e) in all the temperatu re range 250 - 8K. The behavior of kappa(T) at high temperatures (100- 250 K) is very likely to amorphous materials, that can be described by the Einstein model of thermal transport in a lattice of randomly osci llating molecules. The sharp bends on kappa(T) and rho(T) at T similar to 70 K correlate with the known disorder-order phase transition in t he sample Below 70 K the thermal conductivity increases with cooling k (T) similar to T-1, passes through the maximum and further decreases. This behavior is typical for Pierls model of phonon transport in cryst al lattice.