Abstract
We report the first extensive study of longitudinal (ρ a ) and transverse (ρ c ) transport properties versus temperature of the organic quasi one dimensional conductor TMTTF 2 PF 6 over the pressure domain extending from ambient up to 26 kbar. The dimensional cross over observed around 14 kbar separates a 1D region dominated by the Mott-Hubbard gap with activated transport at low pressure from a 3D domain where the temperature range of the metallic behavior, extends up to room temperature along the chains and is progressively increased towards high temperatures in the c direction. In the 1D regime, the different activations obtained from ρ a (T) and ρ c (T) data suggest two different modes of conduction in the longitudinal and transverse directions.