New ET-based organic superconductors with the organometallic anion Cu(CF3)4-

Abstract Electrocrystallization of bis(ethylenedithio)tetrathiafulvalene (ET) with (PNP)Cu(CF 3 ) 4 in 1,1,2-trichloroethane (TCE) results in two new superconductors, κ L -(ET) 2 Cu(CF 3 ) 4 ·(TCE), 1 , with T c = 4.0 K, and κ H -(ET) 2 Cu(CF 3 ) 4 ·(TCE) x , 2 , with T c = 9.2 K. 1 forms well-developed plate-like crystals whose structure was determined by X-ray crystallography. Its band electronic structure is reported. The κ H -phase forms long, thin needle bundles.