The Effect of Disorder on the Metal-insulator and Superconductor Phase Transitions in the ~ and ~ Phases of (bedt -'itf)213

The BEDT-TFF molecules with monovalent anions or iodine complexes form conducting salts, which are less onedimensional (1D) than the compounds of the TTF-TCNQ or (TMTSF)2X families. For example in the c~and 13 modifications of (BEDTTTF)213, abreviated ct, [3 (ET)213, the side by side interaction of the ET molecules is comparable to the face to face interaction [1]. The room tempe-rature conductivity (o) is 20-50 (flcm)-I and, within a factor of two, isotropic in the a-b plane for both compounds while in the c* direction s is 0.02 (f2 cm)-I for ct(ET)213 and 0.1 (f2 cm) -1 for 13 (ET)213. From the point of view of transport properties, they can be considered as quasi-twodimensional (Q-2D) organic conductors.