title: A single-component molecular superconductor.
abstract: The pressure dependence of the resistivities of a single-component molecular conductor, [Ni(hfdt)2] (hfdt = bis(trifluoromethyl)tetrathiafulvalenedithiolate) with semiconducting properties at ambient pressure was examined. The four-probe resistivity measurements were performed up to ∼10 GPa using a diamond anvil cell. The low-temperature insulating phase was suppressed above 7.5 GPa and the resistivity dropped, indicating the superconducting transition occurred around 7.5-8.7 GPa with a maximum Tc (onset temperature) of 5.5 K. The high-pressure crystal and electronic band structures were derived by the first-principle calculations at 6-11 GPa. The crystal was found to retain the semiconducting band structure up to 6 GPa. But the electron and hole Fermi surfaces appear at 8 GPa. These results of the calculations agree well with the observation that the pressure-induced superconducting phase of [Ni(hfdt)2] appeared just above the critical pressure where the low-temperature insulating phase was suppressed.
authors.affiliation: Condensed Molecular Materials Laboratory, RIKEN , Wako-shi, Saitama 351-0198, Japan.
authors.forename: HengBo
authors.initials: H
authors.lastname: Cui
authors.forename: Hayao
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Shoji
authors.initials: S
authors.lastname: Ishibashi
authors.forename: Masaaki
authors.initials: M
authors.lastname: Sasa
authors.forename: Fumitatsu
authors.initials: F
authors.lastname: Iwase
authors.forename: Reizo
authors.initials: R
authors.lastname: Kato
authors.forename: Akiko
authors.initials: A
authors.lastname: Kobayashi