Refinement of the pressure-temperature phase diagram of the organic superconductor with asymmetric anions (TMTSF)(2)FSO3

Abstract

The pressure-temperature phase diagram of the organic superconductor (TMTSF)(2)FSO3 is refined by performing measurements of the interlayer resistance (R-zz) and the longitudinal thermoelectric power (S-xx). In addition to refining the phase transitions previously discussed in the literature, the results show at least two new phase changes at high pressure. The complexity of the phase diagram suggests that the finite electric dipole moment of the asymmetric FSO3 anions, which gives these anions an additional degree of freedom, should be taken into account in addition to their structural ordering.