Strong Coupling of the Iron-Quadrupole and Anion-Dipole Polarizations in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$

Abstract

We use a quantitative convergent beam electron diffraction (CBED) based method to image the valence electron density distribution in Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$. We show a remarkable increase in both the charge quadrupole of the Fe cations and the charge dipole of the arsenic anions upon Co doping from $x=0$ ($T_c=0$ K) to $x=0.1$ ($T_c=22.5$ K). Our data suggest that an unexpected electronic correlation effect, namely strong coupling of Fe orbital fluctuation and anion electronic polarization, is present in iron-based superconductors.

5 pages, 3 figures, accepted by PRL

References in corpus (15)

• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• High-temperature superconductivity in iron-based materials
• Superconductivity at 22 K in Co-doped BaFe2As2 Crystals
• Evidence for an electron nematic phase transition in underdoped iron pnictide superconductors
• Nematic and meta-nematic transitions in the iron pnictides
• Pressure-induced volume-collapsed tetragonal phase of CaFe2As2 as seen via neutron scattering
• Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
• Hall effect and resistivity study of the magnetic transition, carrier content and Fermi liquid behavior in Ba(Fe(1-x) Cox)2As2
• Orbital Order and Spontaneous Orthorhombicity in Iron Pnictides
• Where Are the Extra d Electrons in Transition-Metal Substituted Fe Pnictides?
• Optical properties of the iron-arsenic superconductor BaFe1.85Co0.15As2
• Effect of Co doping on the in-plane anisotropy in the optical spectrum of underdoped Ba(Fe1-xCox)2As2
• Superconductivity-induced optical anomaly in an iron arsenide
• Phonon splitting and anomalous enhancement of infrared-active modes in BaFe${}_2$As${}_2$
• Electronic structure of single-crystalline Sr(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$ probed by x-ray absorption spectroscopy: Evidence for isovalent substitution of Fe${}^{2+}$ by Co${}^{2+}$

Cited by in corpus (11)

• Critical Quadrupole Fluctuations and Collective Modes in Iron Pnictide Superconductors
• High-Tc Superconductivity near the Anion Height Instability in Fe-based Superconductors: Analysis of LaFeAsO${}_{1-x}$H${}_x$
• Charge-Stripe Order in a Parent Compound of Iron-based Superconductors
• Effect of nematic order on the low-energy spin fluctuations in detwinned BaFe${}_{1.935}$Ni${}_{0.065}$As${}_2$
• Phonon anomalies in some iron-telluride materials
• First-principles study of magnetic frustration in FeSe epitaxial films on SrTiO${}_3$
• Anomalous phonon redshift in K-doped BaFe2As2 iron pnictides
• Origin of doping-induced suppression and reemergence of magnetism in LaFeAsO${}_{1-x}$H${}_x$
• The origins of macroscopic quantum coherence in high temperature super conductivity
• Nematic fluctuations in the non-superconducting iron pnictide BaFe${}_{1.9-x}$Ni${}_{0.1}$Cr${}_x$As${}_2$
• Hole-$s_{\pm }$ State Induced by Coexisting Ferro- and Aniferromagnetic and Aniferro-orbital Fluctuations in the Iron Pnictides