PRESSURE DEPENDENCE OF THE THERMOELECTRIC POWER OF TTF-TCNQ.

The thermoelectric power of TTF-TCNQ was measured in the temperature region from 300K-4K for pressures from atmospheric to 15 kbar. The room temperature thermopower decreases from approximately minus 30 mu V/K to approximately minus 10 mu V/K in this pressure range indicating that the relative conductivity of the TTF chain to the TCNQ chain increases with pressure. In the temperature regime of the metal-insulator phase transition it was found that the sign of thermopower changes. The highest temperature transition therefore corresponds to the ″freezing-out″ of carriers on both chains. As pressure increases this transition increasingly effects the TTF chain relative to the TCNQ chain.