Examination of a T-P phase diagram for alpha-(BEDT-TTF)2I3

The paper is concerned with the abrupt metal-dielectric transitions observed at about 100 K (P = 1 bar) in the alpha-phase of such salts as (TMTSF)2ReO4, (TMTSF)2FSO3, and (BEDT-TTF)4(ReO4)2. The temperature dependence of the resistance of the cation-radical salt (BEDT-TTF)2I3, which exists in alpha and beta phases, is investigated experimentally at pressures of up to 11 kbar with a silicon-organic fluid as a pressure transmitting medium. Experimental data reveal the existence of at least three different phase states of the salt; the abrupt transition from metal to dielectric behavior is associated with structural changes.