title: Carrier generation and electronic properties of a single-component pure organic metal.
abstract: Metallic conduction generally requires high carrier concentration and wide bandwidth derived from strong orbital interaction between atoms or molecules. These requisites are especially important in organic compounds because a molecule is fundamentally an insulator; only multi-component salts with strong intermolecular interaction-namely, only charge transfer complexes and conducting polymers-have demonstrated intrinsic metallic behaviour. Herein we report a single-component electroactive molecule, zwitterionic tetrathiafulvalene(TTF)-extended dicarboxylate radical (TED), exhibiting metallic conduction even at low temperatures. TED exhibits d.c. conductivities of 530 S cm-1at 300 K and 1,000 S cm-1at 50 K with copper-like electronic properties. Spectroscopic and theoretical investigations of the carrier-generation mechanism and the electronic states of this single molecular species reveal a unique electronic structure with a spin-density gradient in the extended TTF moieties that becomes, in itself, a metallic state.
authors.affiliation: Research Center for Functional Materials, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba 305-0047, Japan.
authors.forename: Yuka
authors.initials: Y
authors.lastname: Kobayashi
authors.affiliation: Research Center for Functional Materials, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba 305-0047, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Terauchi
authors.affiliation: Research Center for Functional Materials, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba 305-0047, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Sumi
authors.affiliation: Materials Analysis Station, National Institute for Materials Science (NIMS), Sengen 1-2-1, Tsukuba 305-0047, Japan.
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsushita