title: Origin of the Resistive Anisotropy in the Electronic Nematic Phase of BaFe(2)As(2) Revealed by Optical Spectroscopy.
abstract: We perform, as a function of uniaxial stress, an optical-reflectivity investigation of the representative "parent" ferropnictide BaFe(2)As(2) in a broad spectral range, across the tetragonal-to-orthorhombic phase transition and the onset of the long-range antiferromagnetic (AFM) order. The infrared response reveals that the dc transport anisotropy in the orthorhombic AFM state is determined by the interplay between the Drude spectral weight and the scattering rate, but that the dominant effect is clearly associated with the metallic spectral weight. In the paramagnetic tetragonal phase, though, the dc resistivity anisotropy of strained samples is almost exclusively due to stress-induced changes in the Drude weight rather than in the scattering rate, definitively establishing the anisotropy of the Fermi surface parameters as the primary effect driving the dc transport properties in the electronic nematic state.
authors.affiliation: Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland.
authors.forename: C
authors.initials: C
authors.lastname: Mirri
authors.affiliation: Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland.
authors.forename: A
authors.initials: A
authors.lastname: Dusza
authors.affiliation: Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland.
authors.forename: S
authors.initials: S
authors.lastname: Bastelberger
authors.affiliation: Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Chinotti
authors.affiliation: Laboratorium für Festkörperphysik, ETH-Zürich, 8093 Zürich, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Degiorgi
authors.affiliation: Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: J-H
authors.initials: JH
authors.lastname: Chu
authors.affiliation: Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: H-H
authors.initials: HH
authors.lastname: Kuo
authors.affiliation: Geballe Laboratory for Advanced Materials and Department of Applied Physics, Stanford University, Stanford, California 94305, USA and Stanford Institute for Materials and Energy Sciences, SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, California 94025, USA.
authors.forename: I R
authors.initials: IR
authors.lastname: Fisher