Conduction anisotropy of the Bechgaard salts

We report the results of a systematic study on the temperature dependence o f the normal state conductivity, measured along the a, b', and c* axis, in a representative set of Bechgaard salts. The anisotropic electron transport of four compounds are compared: (TMTSF)(2)ClO4, (TMTSF)(2)PF6, (TMTTF)(2)B r and (TMTTF)(2P)F-6. We analyze the tendency, following this order of the compounds, of the metallic ab' plane conductivity change to a semiconductor like behavior, and we discuss the mechanism of inter- and intra-chain tran sport. The c*-direction conduction is determined by the nature of the count er-ion and seems to be irrelevant in this comparison.