Superconductivity induced by extremely high pressure in layered organics, $\beta'$-(BEDT-TTF)2ICl2

An organic Mott insulator, $\beta \prime $-(BEDT-TTF)2ICl2, is metallized by application of extremely high pressure up to 9.0GPa. When the metallic state is stabilized, superconductivity with the highest transition-temperature ($T_{c})$among organic systems appears. The maximum Tcthat we observed was 14.2K(onset) at 8.2GPa. A magnetic-field effect on this superconductivity and normal-state properties are discussed in terms of comparison with other organic superconductors. Key words. Organic superconductor, high pressure.