Universal Phase Diagram of θ-Type TMET-TTP Salts

A new θ-type TMET-TTP (2-[4,5-bis(thiomethyl)-1,3-dithiol-2-ylidene]-5-(4,5- ethylenedithio-1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene) salt (TMET-TTP) 2 HSO 4 , which has smaller dihedral angle (116°), and has 2:1 composition, is prepared. This salt undergoes a M-I transition at around 100 K. The ESR measurement indicates that the low-temperature insulating state of this complex is paramagnetic. Thanks to this exceptional salt, a universal phase diagram of θ-type TTP salts can be discussed similarly to θ-type ET salts. In the θ-type ET salts, the universal phase diagram holds in the uniform quarter-filled band. However, our works in the θ-type TMET-TTP salts prove that the universal phase diagram is not largely influenced by the band-filling and the position of E F .