C-Axis Thermoelectric Power of Graphite Intercalation Compounds with Iodine Monochrolide

抄録

Thermoelectric power in the c-direction (S_c) of iodine monochrolide-graphite intercalation compounds (ICl-GICs) exhibits a gradual slope change around 80--100, K, though above and below the temperature range S_c is nearly linearly temperature-dependent. This behavior implies that the major contribution to S_c comes from the diffusion term (S_d), and the absence of the phonon drag term (S_p) in contrast with the in-plane component (S_a) is due to the very weak interlayer interaction. The slope change is ascribed to the change of the energy dependence of Γ_ph(E) with temperature, where Γ_ph(E) is the scattering rate of carriers due to the in-plane phonons. Γ_ph(E) and p_ph≡ -E(d/dE), log, Γ_ph(E), which are included in the expression of S_c, are calculated. The calculation can provide a qualitative explanation of the observed result of stage-1 compound.