title: Infrared electronic absorption in a single-component molecular metal.
abstract: The infrared spectra of the crystal of transition metal complex molecules with extended-TTF ligands, Ni(tmdt)2, which is the first single-component molecular metal that has a stable metallic state even at low temperatures, exhibited an extremely low-energy electronic absorption around 2200 cm-1 (tmdt = trimethylenetetrathiafulvalenedithiolate). The systematic shift of the absorption peaks for molecules similar to Ni(tmdt)2, which range from metallic to semiconducting crystals, shows that the single-component molecular conductors are composed of molecules with unprecedentedly small HOMO-LUMO gaps.
authors.affiliation: Research Centre for Spectrochemistry, Graduate School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Sasa
authors.forename: Wakako
authors.initials: W
authors.lastname: Suzuki
authors.forename: Emiko
authors.initials: E
authors.lastname: Fujiwara
authors.forename: Hisashi
authors.initials: H
authors.lastname: Tanaka
authors.forename: Madoka
authors.initials: M
authors.lastname: Tokumoto
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Okano
authors.forename: Hideki
authors.initials: H
authors.lastname: Fujiwara
authors.forename: Hayao
authors.initials: H
authors.lastname: Kobayashi