MOLECULAR DESIGN AND SOLID-STATE PROPERTIES OF NEW SUPERCONDUCTORS AND MOLECULAR-METALS WITH ORDERED SPIN STRUCTURES

The authors have examined several new types of molecular metals including three new superconductors, θ-(BEDT-TTF)2I3, κ-(BEDT-TTF)2I3 and [(CH3)4N][Ni(dmit)2]2. According to molecular design analyses based on simple tight-binding band calculations, there are two ways to avoid the metal-insulator transition encountered in one-dimensional systems. They are to design 2D metals and multi-Fermi surfaces systems. The 2D layered molecular superconductors, θ-and κ-(BEDT-TTF)2I3, Ni(dmit)2 superconductors and magnetic molecular metals, R1, R2-DCNQI2Cu(R1, R2=CH3, CH3O, Br, Cl) are described from the molecular design point of view.