Charge localization in organic conductors (TM)2X: The influence of anion ordering
Résumé
An investigation of the different contributions leading to charge localization in a 1/2 or 1/4 filled band 1D conductor has been conducted through a study of transport properties in the solid solution [(TMTSF)1-x (TMTTF)x]2ReO4. The existence of an ordering transition of the allions allows to identify two contributions to the electronic potential with wave vector 4kF. A dominant on-sitc 4kF potential besides the bond contribution is revealed when Umklapp scattering is pertinent via the weakening of the localization arising at the (0, 1/2, 1/2) anion ordering which is stabilized under pressure in the compound [(TMTSF)0.5 (TMTTF)0.5]2ReO4 at variance with the enhancement of localization observed in the homomolecular (TMTTF)2ReO4 material.