title: Anisotropic optical spectra of PrBa2Cu4O8: possible Tomonaga-Luttinger liquid response of the quasi-one-dimensional metallic CuO double chains.
abstract: The optical spectra of PrBa2Cu4O8 show large in-plane anisotropy. For the a polarization (E perpendicular chain), the spectrum is characterized by a gap of 1.4 eV, indicating the charge-transfer insulating nature of the CuO2 planes. For the metallic chain direction (E // b), the spectrum deviates from a simple Drude response; reflectivity R(b)(omega) shows a sharp edge at approximately 1 eV but it also shows a dip at approximately 15 meV, which splits the conductivity spectrum into two parts--a zero-energy mode with small weight and a pronounced 40 meV mode. These features are discussed in terms of a Tomonaga-Luttinger liquid in a doped 1D Mott insulator and compared with 1D Bechgaard salts.
authors.affiliation: Department of Physics, Nagoya University, Nagoya 464-8602, Japan. k46291a@nucc.cc.nagoya-u.ac.jp
authors.forename: K
authors.initials: K
authors.lastname: Takenaka
authors.forename: K
authors.initials: K
authors.lastname: Nakada
authors.forename: A
authors.initials: A
authors.lastname: Osuka
authors.forename: S
authors.initials: S
authors.lastname: Horii
authors.forename: H
authors.initials: H
authors.lastname: Ikuta
authors.forename: I
authors.initials: I
authors.lastname: Hirabayashi
authors.forename: S
authors.initials: S
authors.lastname: Sugai
authors.forename: U
authors.initials: U
authors.lastname: Mizutani