title: Rotation of orbital stripes and the consequent charge-polarized state in bilayer manganites.
abstract: Nanoscale self-organization of electrons is ubiquitously observed in correlated electron systems such as complex oxides of transition metals. The phenomenon of charge ordering (CO) or the formation of charge stripes, as observed for layered-structure cuprates and nickelates, is one such example. Among them, CO in manganites is closely tied to the orbital degree of freedom of 3d electrons, leading to staggered orbital ordering or the formation of orbital stripes in the layered structure. Here, we describe the phenomena of thermally induced rotation of the orbital stripes by 90( composite function) for bilayered manganite crystals with half hole doping, that is, a 1:1 ratio of Mn3+/Mn4+. The rotation of orbital stripes and the consequent CO coupled with the underlying lattice distortion were found to produce the charge-polarized state, as also shown by its optical second-harmonic generation activity.
authors.affiliation: Spin Superstructure Project, ERATO, Japan Science and Technology Agency (JST), Tsukuba, Ibaraki 305-8562, Japan. yusuke-tokunaga@aist.go.jp
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tokunaga
authors.forename: Thomas
authors.initials: T
authors.lastname: Lottermoser
authors.forename: Yunsang
authors.initials: Y
authors.lastname: Lee
authors.forename: Reiji
authors.initials: R
authors.lastname: Kumai
authors.forename: Masaya
authors.initials: M
authors.lastname: Uchida
authors.forename: Takahisa
authors.initials: T
authors.lastname: Arima
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Tokura