About cookies on this site Our websites require some cookies to function properly (required). In addition, other cookies may be used with your consent to analyze site usage, improve the user experience and for advertising. For more information, please review your options. By visiting our website, you agree to our processing of information as described in IBM’sprivacy statement. To provide a smooth navigation, your cookie preferences will be shared across the IBM web domains listed here.
Paper
Conductivity and thermopower studies of bis- tetramethyltetraselenafulvalenium hexafluorophosphide, bis- tetramethyltetrathiafulvalenium hexafluorophosphide, and their solid solutions, (TMTSF1-xTMTTFx)2PF6
Abstract
The conductivity and the thermoelectric power S have been studied experimentally on the organic conductors bis-tetramethyltetraselenafulvalenium hexafluorophosphide [(TMTSF)2PF6] and bis-tetramethyltetrathiafulvalenium hexafluorophosphide [(TMTTF)2PF6] and their solid solutions: (TMTSF1-xTMTTFx)2PF6. Dramatic effects are seen in already when dilute concentrations of TMTTF molecules are introduced in the TMTSF chains, and for x=0.1, shows generally activated behavior. The thermopower, on the contrary, remains basically unaffected for x at least as large as 0.25. These unusual findings are attributed to the small transverse transfer integral tb associated with the TMTTF molecule, which leads to large on-site Coulomb repulsion. The parallel transfer integrals ta appear to be very similar for the two constituent molecules. A slight x dependence of S, appearing below approximately 100 K, is attributed to enhanced one-dimensionality when the amount of TMTTF is increased. Close to and below the spin-density-wave ordering temperature, more marked x dependences appear, indicative of impurities. The x=0.85 salt behaves generally similar to the pristine TMTTF material, though dominated by additional impurity levels. © 1984 The American Physical Society.