title: Optical Spectroscopic Studies of the Metal-Insulator Transition Driven by All-In-All-Out Magnetic Ordering in 5d Pyrochlore Cd(2)Os(2)O(7).
abstract: We investigated the metal-insulator transition (MIT) driven by all-in-all-out (AIAO) antiferromagnetic ordering in the 5d pyrochlore Cd(2)Os(2)O(7) using optical spectroscopy and first-principles calculations. We showed that the temperature evolution in the band-gap edge and free carrier density were consistent with rigid upward (downward) shifts of electron (hole) bands, similar to the case of Lifshitz transitions. The delicate relationship between the band gap and free carrier density provides experimental evidence for the presence of an AIAO metallic phase, a natural consequence of such MITs. The associated spectral weight change at high energy and first-principles calculations further support the origin of the MIT from the band shift near the Fermi level. Our data consistently support that the MIT induced by AIAO ordering in Cd(2)Os(2)O(7) is not close to a Slater type but instead to a Lifshitz type.
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.
authors.forename: C H
authors.initials: CH
authors.lastname: Sohn
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.
authors.forename: Hogyun
authors.initials: H
authors.lastname: Jeong
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.|Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 44919, Republic of Korea.
authors.forename: Hosub
authors.initials: H
authors.lastname: Jin
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.
authors.forename: Soyeon
authors.initials: S
authors.lastname: Kim
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.
authors.forename: L J
authors.initials: LJ
authors.lastname: Sandilands
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.
authors.forename: H J
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Department of Physics, Chungbuk National University, Cheongju, Chungbuk 28644, Republic of Korea.
authors.forename: K W
authors.initials: KW
authors.lastname: Kim
authors.affiliation: Department of Physics, Hanyang University, Seoul 04763, Republic of Korea.
authors.forename: S J
authors.initials: SJ
authors.lastname: Moon
authors.affiliation: Department of Physics, Chonbuk National University, Jeonju 54896, Republic of Korea.
authors.forename: Deok-Yong
authors.initials: DY
authors.lastname: Cho
authors.affiliation: Materials Research Center for Element Strategy, Tokyo Institute of Technology, Kanagawa 226-8503, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Yamaura
authors.affiliation: ISSP, University of Tokyo, Kashiwa 277-8581, Japan.
authors.forename: Z
authors.initials: Z
authors.lastname: Hiroi
authors.affiliation: Center for Correlated Electron Systems, Institute for Basic Science (IBS), Seoul 08826, Republic of Korea.|Department of Physics and Astronomy, Seoul National University (SNU), Seoul 08826, Republic of Korea.
authors.forename: T W
authors.initials: TW
authors.lastname: Noh