Charge Ordered Insulating State in DODHT Salts

Radical salts based on DODHT [(1,4-dioxane-2,3-diyldithio)dihydrotetrathiafulvalene] are semiconductors at ambient pressure, but some salts (PF6, AsF6, and BF4·H2O salts) exhibit supuerconducting transition under hydrostatic pressure. X-ray diffraction and magnetic susceptibility measurements at ambient pressure for PF6 salt revealed that the insulating phase at ambient pressure corresponds to a charge ordering (CO) state with stripe-type charge pattern. While the similar magnetic behavior was observed for BF4 salt, temperature dependence of magnetic susceptibility of AsF6 salt is quite different from those of the other salts.