Organic superconductors.

The present status of organic superconductors of charge-transfer (CT) type based on donor molecules is reviewed. Along with the superconducting phases of such materials and also of oxide superconductors, reside spin-ordered phases such as spin-density wave (SDW) and antiferromagnetic (AF) phases. We briefly describe the recent development of superconductors having a superconducting phase next to a spin-disorder state (quantum spin liquid state). In addition to the CT type superconductors, there are a few single-component superconductors under high pressure.