Mircowave Conductivity and Thermoelectric Power of Some Ternary Salts of TCNQ and Iodine

For a series of ternary compounds made with TCNQ, iodine, and quaternary ammonium the complex dielectric constant at microwave frequency (9.1 GHz) and the thermoelectric power are measured in the emperature range 80 to 300 K. Above a “Peierls-like” transition the thermoelectric power results are discussed in terms of an inrinsic semiconductor with Hubbard gap. For interpretation of the microwave results in the high-temperature phase an interrupted strand model can be applied, whereas in the low-temperature phase the localized electron concept is important. Pour une serie des sels ternaires composes du TCNQ, d'iode et d'ammonium quaternaire, on a etudie, en fonction de la temperature (80 a 300 K), le pouvoir thermoelectrique et la constante dielectrique a und frequence microonde (9,1 GHz). On a associe le comportement du pouvoir thermoeletrique au-dessus de la transition de “type de Peierls” a celui d'un semiconduceur presentant un gap de Hubbard. Pour interpreter les resultats microondes dans la phase haute-temperature on peut appliquer le modele, de segments coupes alors que la phase basse-temperature l'influence de la localization des elerons peut etre impotante.