title: Possible phase transition deep inside the hidden order phase of ultraclean URu2Si2.
abstract: To elucidate the underlying nature of the hidden order (HO) state in heavy-fermion compound URu(2)Si(2), we measure electrical transport properties of ultraclean crystals in a high field, low temperature regime. Unlike previous studies, the present system with much less impurity scattering resolves a distinct anomaly of the Hall resistivity at H;{*} = 22.5 T, well below the destruction field of the HO phase = or approximately 36 T. In addition, a novel quantum oscillation appears above a magnetic field slightly below H;{*}. These results indicate an abrupt reconstruction of the Fermi surface, which implies a possible phase transition well within the HO phase caused by a band-dependent destruction of the HO parameter.
authors.affiliation: Department of Physics, Kyoto University, Kyoto 606-8502, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Shishido
authors.forename: K
authors.initials: K
authors.lastname: Hashimoto
authors.forename: T
authors.initials: T
authors.lastname: Shibauchi
authors.forename: T
authors.initials: T
authors.lastname: Sasaki
authors.forename: H
authors.initials: H
authors.lastname: Oizumi
authors.forename: N
authors.initials: N
authors.lastname: Kobayashi
authors.forename: T
authors.initials: T
authors.lastname: Takamasu
authors.forename: K
authors.initials: K
authors.lastname: Takehana
authors.forename: Y
authors.initials: Y
authors.lastname: Imanaka
authors.forename: T D
authors.initials: TD
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Haga
authors.forename: Y
authors.initials: Y
authors.lastname: Onuki
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda