New ambient pressure organic superconductors κH- and κL-(DMEDO-TSeF)2[Au(CN)4](THF)

Abstract

We have developed two novel organic superconductors κ_H- and κ_L-(DMEDO-TSeF)₂[Au(CN)₄](THF) (DMEDO-TSeF = dimethyl(ethylenedioxy)tetraselenafulvalene) with the onset transition temperatures of 4.8 K for the κ_H-phase and 3.0 K for the κ_L-phase at ambient pressure, where DMEDO-TSeF is the second example following tetramethyltetraselenafulvalene (TMTSF) after an interval of 25 years as a sulfur-free donor providing a bulk organic superconductor.