Tamperature Dependence of Magnetic Susceptibilities of (TTT)(TCNQ) and (TTT)(TCNQ)2

Article abstract of DOI:10.1246/bcsj.57.26

Static magnetic susceptibility and ESR studies of 1:1 and 1:2 charge-transfer complexes of naphthaceno<5,6-cd:11,12-c'd'>bis<1,2>dithiole and 2,2'-(2,5-cyclohexadiene-1,4-diylidene)bis(propanedinitrile) <(TTT)(TCNQ) and (TTT)(TCNQ)2> in the temperature region of 2-310 K are described. (TTT)(TCNQ)2 exhibits a temperature dependent spin susceptibility, while the spin susceptibility of (TTT)(TCNQ) is almost independent of temperature.Spin susceptibilities of the TTT and TCNQ chains, which are evaluated with a g-value decomposition technique, are interpreted in terms of aone-dimensional Hubbard model.In both complexes, the on-site Coulomb repulsion is comparable with or larger than the band width on the TCNQ chains and is smaller on the TTT chains.Two magnetic phase transitions are observed in (TTT)(TCNQ)2.The transition is driven in each chain independently by the Peierls instability.The amount of charge transfer in (TTT)(TCNQ) is determined to be 0.73+/-0.05 from an X-ray photoelectron spectroscopic study.