A Molecular Superconductor Having a Solid-Crossing Column Structure, Me4N[Ni(dmit)2]2

Abstract
Electrical resistivity, thermoelectric power, and magnetic susceptibility were investigated under ambient pressure for Me4N[Ni(dmit)2]2 which exhibits superconductivity under applied pressure. The metal-insulator transition of this salt was reexamined, and then the transition temperature was determined to be about 40 K from the temperature dependence of the thermoelectric power and electrical resistivity. The magnetic susceptibility revealed another phase transition at 11 K from paramagnetic insulator to diamagnetic insulator. This newly-found transition was attributed to the spin-Peierls transition.