Transport Properties of the Metallic State of TMTSF-DMTCNQ

The authors report the transport properties (longitudinal and transverse conductivity, magnetoresistance and thermopower) of TMTSF-DMTCNQ for pressures up to 13 kbar and temperatures down to 1.2K together with the phase diagram which results from these measurements. The most striking results are the occurrence of a first order insulator-metal low temperature transition as pressure is increased above 9.75 kbar and the properties of the metallic state. At pressures sufficiently high to quench the Peierls transition the helium temperature conductivity is greater than that found in any organic conductor at any temperature (σ∥≳105 (Ωcm)-1) and an enormous magnetoresistance Δρ/ρ≈15) is found for a field of 75 kOe perpendicular to the conducting chains