title: Band Structure and Terahertz Optical Conductivity of Transition Metal Oxides: Theory and Application to CaRuO(3).
abstract: Density functional plus dynamical mean field calculations are used to show that in transition metal oxides, rotational and tilting (GdFeO(3)-type) distortions of the ideal cubic perovskite structure produce a multiplicity of low-energy optical transitions which affect the conductivity down to frequencies of the order of 1 or 2 mV (terahertz regime), mimicking non-Fermi-liquid effects even in systems with a strictly Fermi-liquid self-energy. For CaRuO(3), a material whose measured electromagnetic response in the terahertz frequency regime has been interpreted as evidence for non-Fermi-liquid physics, the combination of these band structure effects and a renormalized Fermi-liquid self-energy accounts for the low frequency optical response which had previously been regarded as a signature of exotic physics. Signatures of deviations from Fermi-liquid behavior at higher frequencies (∼100  meV) are discussed.
authors.affiliation: Institute for Theoretical Solid State Physics, JARA-FIT and JARA-HPC, RWTH Aachen University, 52056 Aachen, Germany.
authors.forename: Hung T
authors.initials: HT
authors.lastname: Dang
authors.affiliation: Jožef Stefan Institute, Jamova 39, SI-1000 Ljubljana, Slovenia.
authors.forename: Jernej
authors.initials: J
authors.lastname: Mravlje
authors.affiliation: Collège de France, 11 place Marcelin Berthelot, 75005 Paris, France.|Centre de Physique Théorique, Ecole Polytechnique, CNRS, 91128 Palaiseau Cedex, France.|DQMP, Université de Genève, 24 quai Ernest-Ansermet, 1211 Genève 4, Switzerland.
authors.forename: Antoine
authors.initials: A
authors.lastname: Georges
authors.affiliation: Department of Physics, Columbia University, New York, New York 10027, USA.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Millis