title: Pseudogap dependence of the optical conductivity spectra of Ca3Ru2O7: a possible contribution of the orbital flip excitation.
abstract: Optical spectra of a double-layered perovskite ruthenate Ca3Ru2O7 show a pseudogap opening around 200 cm(-1) below 50 K, which is attributable to the partial k-space gap opening due to the density wave instability. Unlike most other density wave materials, Ca3Ru2O7 has spectral weight redistributions, not near the energy gap region, but at a much higher energy region around 800 cm(-1). As a possible origin of these intriguing features, we discuss the orbital flip excitation in the density wave ground state.
authors.affiliation: ReCOE & FPRD, Department of Physics and Astronomy, Seoul National University, Seoul 151-747, Korea.
authors.forename: J S
authors.initials: JS
authors.lastname: Lee
authors.forename: S J
authors.initials: SJ
authors.lastname: Moon
authors.forename: B J
authors.initials: BJ
authors.lastname: Yang
authors.forename: Jaejun
authors.initials: J
authors.lastname: Yu
authors.forename: U
authors.initials: U
authors.lastname: Schade
authors.forename: Y
authors.initials: Y
authors.lastname: Yoshida
authors.forename: S-I
authors.initials: SI
authors.lastname: Ikeda
authors.forename: T W
authors.initials: TW
authors.lastname: Noh