Mircowave conductivity and thermoelectric power of some ternary salts of TCNQ and iodine

Abstract

For a series of ternary compounds made with TCNQ, iodine, and quaternary ammonium the complex dielectric constant a t microwave frequency (9.1 GHz) and the thermoelectric power are measured in the temperature range 80 t o 300 I ( . Above a "Peierls-like" transition the thermoelectric power results are discussed in terms of a n intrinsic semiconductor with Hubbard gap. For interpretation of the microwave results in the high-temperature phase a n interrupted strand model can be applied, whereas in the low-temperature phase the localized electron concept i s important.Pour une sBrie des sels ternaires compos6s d u TCNQ, d'iode e t d'ammonium quaternaire, on a ktudiB. en fonction de la temperature (SO Q. 300 K), le pouvoir thermo8lectrique et la constante dielectrique B une frhquence microonde (9,l GHz). On a associS: le comportement du pouvoir thermohlectrique au-dessus de la transition de "type de Peierls" B celui d'un semiconducteur present. a n t u n gap de Hubbard. Pour interpreter les resultats microondes d a m la phase haute-temperature on peut appliquer le modele, de segments coup6s alors que d a m la phase basse-temperature I'influence de la localization des Blectrons peut atre importante. R. SWIETLIK, G. MIHALY, and 9. SELHA~S