title: Synthesis, crystal structure, and electronic properties of high-pressure PdF2-type oxides MO2 (M = Ru, Rh, Os, Ir, Pt).
abstract: The polycrystalline MO2's (HP-PdF2-type MO2, M = Rh, Os, Pt) with high-pressure PdF2 compounds were successfully synthesized under high-pressure conditions for the first time, to the best of our knowledge. The crystal structures and electromagnetic properties were studied. Previously unreported electronic properties of the polycrystalline HP-PdF2-type RuO2 and IrO2 were also studied. The refined structures clearly indicated that all compounds crystallized into the HP-PdF2-type structure, M(4+)O(2-)2, rather than the pyrite-type structure, M(n+)(O2)(n-) (n < 4). The MO2 compounds (M = Ru, Rh, Os, Ir) exhibited metallic conduction, while PtO2 was highly insulating, probably because of the fully occupied t2g band. Neither superconductivity nor a magnetic transition was detected down to a temperature of 2 K, unlike the case of 3d transition metal chalcogenide pyrites.
authors.affiliation: Department of Chemistry, Gakushuin University , 1-5-1 Mejiro, Toshima-ku, Tokyo 171-8588, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Shirako
authors.forename: Xia
authors.initials: X
authors.lastname: Wang
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Tsujimoto
authors.forename: Kie
authors.initials: K
authors.lastname: Tanaka
authors.forename: Yanfeng
authors.initials: Y
authors.lastname: Guo
authors.forename: Yoshitaka
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Nemoto
authors.forename: Yoshio
authors.initials: Y
authors.lastname: Katsuya
authors.forename: Youguo
authors.initials: Y
authors.lastname: Shi
authors.forename: Daisuke
authors.initials: D
authors.lastname: Mori
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Kojitani
authors.forename: Kazunari
authors.initials: K
authors.lastname: Yamaura
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Inaguma
authors.forename: Masaki
authors.initials: M
authors.lastname: Akaogi