Orbital Order and Spontaneous Orthorhombicity in Iron Pnictides

Abstract

A growing list of experiments show orthorhombic electronic anisotropy in the iron pnictides, in some cases at temperatures well above the spin density wave transition. These experiments include neutron scattering, resistivity and magnetoresistance measurements, and a variety of spectroscopies. We explore the idea that these anisotropies stem from a common underlying cause: orbital order manifest in an unequal occupation of $d_{xz}$ and $d_{yz}$ orbitals, arising from the coupled spin-orbital degrees of freedom. We emphasize the distinction between the total orbital occupation (the integrated density of states), where the order parameter may be small, and the orbital polarization near the Fermi level which can be more pronounced. We also discuss light-polarization studies of angle-resolved photoemission, and demonstrate how x-ray absorption linear dichroism may be used as a method to detect an orbital order parameter.

Orig.: 4+ pages; Rev.: 4+ pages with updated content and references

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Cited by in corpus (51)

• Nematic and meta-nematic transitions in the iron pnictides
• Iron-Based Superconductors: current status of materials and pairing mechanism
• Orbital-driven nematicity in FeSe
• Reconstruction of Band Structure Induced by Electronic Nematicity in an FeSe Superconductor
• Nematic spin correlations in the tetragonal state of uniaxial strained BaFe2-xNixAs2
• Unprecedented anisotropic metallic state in BaFe2As2 revealed by optical spectroscopy
• Manifestations of nematic degrees of freedom in the magnetic, elastic, and superconducting properties of the iron pnictides
• Low-energy microscopic models for iron-based superconductors: a review
• The origin of nematic order in FeSe
• Spontaneous Formation of Altermagnetism from Orbital Ordering
• Antiferromagnetic ordering in the absence of a structural distortion in Ba(Fe{1-x}Mn{x})2As2
• Conductivity anisotropy in the antiferromagnetic state of iron pnictides
• Effect of Co doping on the in-plane anisotropy in the optical spectrum of underdoped Ba(Fe1-xCox)2As2
• Orbital differentiation and the role of orbital ordering in the magnetic state of Fe superconductors
• Distinguishing spin-orbit coupling and nematic order in the electronic spectrum of iron-based superconductors
• Spin-state transition in the Fe-pnictides
• Thermopower as sensitive probe of electronic nematicity in iron pnictides
• Emergence of Orbital Nematicity in the Tetragonal Phase of BaFe${}_2$(As${}_{1-x}$P${}_x$)${}_2$
• Emergent defect states as a source of resistivity anisotropy in the nematic phase of iron pnictides
• Optical conductivity and Raman scattering of iron superconductors
• Manipulation of gap nodes by uniaxial strain in iron-based superconductors
• The relationship between transport anisotropy and nematicity in FeSe
• Spin-orbital interplay and topology in the nematic phase of iron pnictides
• Magnetic order in orbital models of the iron pnictides
• Neutron-scattering measurements of the spin excitations in LaFeAsO and Ba(Fe${}_{0.953}$Co${}_{0.047}$)${}_2$As${}_2$: Evidence for a sharp enhancement of spin fluctuations by nematic order
• Spin and Orbital Characters of Excitations in Iron Arsenide Superconductors Revealed by Simulated Fe L-Edge RIXS
• Spin excitations in the nematic phase and the metallic stripe spin-density wave phase of iron pnictides
• Spin excitations in optimally P-doped BaFe2(As0.7P0.3)2superconductor
• Impact of Dynamic Orbital Correlations on Magnetic Excitations in the Normal State of Iron-Based Superconductors
• Spontaneous orbital polarization in the nematic phase of FeSe
• Transport and magnetic properties of La-doped CaFe${}_2$As${}_2$
• Origin of doping-induced suppression and reemergence of magnetism in LaFeAsO${}_{1-x}$H${}_x$
• Diverging Nematic Susceptibility, Physical Meaning of T* scale, and Pseudogap in the Spin Fermion Model for Pnictides
• Momentum-resolved measurement of electronic nematic susceptibility in the FeSe${}_{0.9}$S${}_{0.1}$ superconductor
• Reversed anisotropy of the in-plane resistivity in the antiferromagnetic phase of iron tellurides
• Optical observation of spin-density-wave fluctuations in Ba122 iron-based superconductors
• Orbital Nematic Order and Interplay with Magnetism in the Two-Orbital Hubbard Model
• Spin excitation anisotropy in the paramagnetic tetragonal phase of BaFe2 As2
• Anomalous spectral weight transfer in the nematic state of iron-selenide superconductor
• Non-Fermi Liquid behavior at the Orbital Ordering Quantum Critical Point in the Two-Orbital Model
• Revealing the degree of magnetic frustration by non-magnetic impurities
• Study of antiferromagnetic and nematic phase transitions in $BaF{e}_2(A{s}_{1-x}{P}_x{)}_2$ by AC micro-calorimetry and SQUID magnetometry
• Electronic origin of structural transition in 122 Fe based superconductors
• Nematic fluctuations in the non-superconducting iron pnictide BaFe${}_{1.9-x}$Ni${}_{0.1}$Cr${}_x$As${}_2$
• Uniaxial stress effect on the electronic structure of quantum materials
• Electronic structure, spin excitations, and orbital ordering in a three-orbital model for iron pnictides
• Magnetic softness in iron-based superconductors
• Suppression of nematicity by tensile strain in multilayer FeSe/SrTiO${}_3$ films
• Atomic-scale imaging of electronic nematicity in ferropnictides
• Edwards-Anderson parameter and local Ising-nematicity in FeSe revealed via NMR spectral broadening
• Anisotropy in the thermal hysteresis of resistivity and charge density wave nature of single crystal SrFeO3-delta: X-ray absorption and photoemission studies