title: Hydrogen bond-promoted metallic state in a purely organic single-component conductor under pressure.
abstract: Purely organic materials are generally insulating. Some charge-carrier generation, however, can provide them with electrical conductivity. In multi-component organic systems, carrier generation by intermolecular charge transfer has given many molecular metals. By contrast, in purely organic single-component systems, metallic states have rarely been realized although some neutral-radical semiconductors have been reported. Here we uncover a new type of purely organic single-component molecular conductor by utilizing strong hydrogen-bonding interactions between tetrathiafulvalene-based electron-donor molecules. These conductors are composed of highly symmetric molecular units constructed by the strong intra-unit hydrogen bond. Moreover, we demonstrate that, in this system, charge carriers are produced by the partial oxidation of the donor molecules and delocalized through the formation of the symmetric intra-unit hydrogen bonds. As a result, our conductors show the highest room-temperature electrical conductivity and the metallic state under the lowest physical pressure among the purely organic single-component systems, to our knowledge.
authors.affiliation: The Institute for Solid State Physics, The University of Tokyo, Kashiwa, Chiba 277-8581, Japan.
authors.forename: Takayuki
authors.initials: T
authors.lastname: Isono
authors.forename: Hiromichi
authors.initials: H
authors.lastname: Kamo
authors.forename: Akira
authors.initials: A
authors.lastname: Ueda
authors.forename: Kazuyuki
authors.initials: K
authors.lastname: Takahashi
authors.forename: Akiko
authors.initials: A
authors.lastname: Nakao
authors.forename: Reiji
authors.initials: R
authors.lastname: Kumai
authors.forename: Hironori
authors.initials: H
authors.lastname: Nakao
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Youichi
authors.initials: Y
authors.lastname: Murakami
authors.forename: Hatsumi
authors.initials: H
authors.lastname: Mori