M. Weger et al., FREEZEOUT OF THE ELECTRICAL-RESISTIVITY IN (BEDT-TTF)(2)I-3 BELOW 20-K, Journal of physics. Condensed matter, 5(45), 1993, pp. 8569-8578
We have measured the temperature (T) dependence of the resistivity rho
of the beta and kappa phases of (BEDT-TTF)(2)I-3 from 300 K down to T
-c (similar to 1.3 K and similar to 4 K for the beta and kappa phases,
respectively). Between 100 K and 20 K, rho proportional to T-2. Below
20 K, the resistivity falls below the T-2 law. We calculate the resis
tivity due to electron-electron scattering and find that this contribu
tion is far too small to account for the measured resistivity, besides
being inconsistent with the freezeout below 20 K. We suggest that the
resistivity is due to electron-phonon scattering, described by a nove
l mechanism that has been proposed for the high-T-c cuprates. We also
suggest that this mechanism accounts for tbe T-2 law observed in mater
ials such as TiS2, Nb-doped SrTiO3, and intercalated graphite.