THE MEYER-NELDEL RULE IN FULLERENES

We report that the thermally activated conductivity in several fullere ne systems obeys the Meyer-Nelder (MN) rule, sigma=sigma(00)e(Delta E/ kT0)e(.)(-Delta E/kT) We found that the MN conductivity sigma(00) and the characteristic energy kT(0) have a strong correlation, which is in good agreement with the prediction of the model proposed by Crandall [R. S. Crandall, Phys. Rev. B 43, 4057 (1991)] and Chen [Y. F. Chen an d S. F. Huang, Phys. Rev. B 44, 13 775 (1991)]. In this model, the ori gin of the MN rule is attributed to the exponential energy distributio n of the defect traps. A similar correlation between sigma(00) and kT( 0) is also found in chalcogenide glasses. (C) 1998 American Institute of Physics.