Crystal Structures and Physical Properties of DMET Superconductors

Abstract

Since the first discovery of superconductivity in an organic material [1], a number of organic superconductors have been found in the TMTSF and BEDT-TTF families. However, there are many differences in the crystal structures and physical properties between the two families. Recently we have discovered seven organic superconductors in the family of the unsymmetrical donor DMET [2–6]. These new superconductors are the first ones based on an unsymmetrical molecule. They are also useful for understanding the organic superconductors systematically, because the DMET salts seem to link the TMTSF and BEDT-TTF families: DMET has halves of the structures of TMTSF and BEDT-TTF. Indeed, the investigation of the temperature dependence of the resistivity revealed that DMET superconductors can be classified into three groups: one group is similar to the TMTSF salts, another is similar to the BEDT-TTF salts [7,8]. In this report we summarize the crystal structures and the physical properties of DMET superconductors.