Spin excitations in the excitonic spin-density-wave state of the iron pnictides

Abstract

Motivated by the iron pnictides, we examine the spin excitations in an itinerant antiferromagnet where a spin-density wave (SDW) originates from an excitonic instability of nested electron-like and hole-like Fermi pockets. Using the random phase approximation (RPA), we derive the Dyson equation for the transverse susceptibility in the excitonic SDW state. The Dyson equation is solved for two different two-band models, describing an antiferromagnetic insulator and metal, respectively. We determine the collective spin-wave dispersions and also consider the single-particle continua. The results for the excitonic models are compared with each other and also contrasted with the well-known SDW state of the Hubbard model. Despite the qualitatively different SDW states in the two excitonic models, their magnetic response shows many similarities. We conclude with a discussion of the relevance of the excitonic SDW scenario to the iron pnictides.

17 pages, 18 figures, v2: expanded discussion of spin-wave velocity, added references

References in corpus (39)

• Superconductivity at 38 K in the iron arsenide (Ba1-xKx)Fe2As2
• Magnetic Order versus superconductivity in the Iron-based layered La(O1-xFx)FeAs systems
• Unconventional pairing originating from disconnected Fermi surfaces in superconducting LaFeAsO${}_{1-x}$F${}_x$}
• LaFeAsO${}_{1-x}$F${}_x$: A low carrier density superconductor near itinerant magnetism
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Structural and magnetic phase diagram of CeFeAsO1-xFx and its relationship to high-temperature superconductivity
• Magnetism, superconductivity, and pairing symmetry in Fe-based superconductors
• Strong Correlations and Magnetic Frustration in the High Tc Iron Pnictides
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Origin of the ~150 K Anomaly in LaOFeAs; Competing Antiferromagnetic Superexchange Interactions, Frustration, and Structural Phase Transition
• A minimal two-band model for the superconducting Fe-pnictides
• The electronic phase diagram of the LaO1-xFxFeAs superconductor
• Spin-orbital frustrations and anomalous metallic state in iron-pnictide superconductors
• Multiband magnetism and superconductivity in Fe-based compounds
• Phase transitions in LaFeAsO: structural, magnetic, elastic, and transport properties, heat capacity and Mossbauer spectra
• Theory of magnetic excitations in iron-based layered superconductors
• Nodal Spin Density Wave and band topology of the FeAs based materials
• Low energy spin waves and magnetic interactions in SrFe${}_2$As${}_2$
• Itinerant magnetic excitations in antiferromagnetic CaFe2As2
• Anisotropic itinerant magnetism and spin fluctuations in BaFe2As2: A neutron scattering study
• Quantum oscillations in the parent magnetic phase of an iron arsenide high temperature superconductor
• Neutron Studies of the Iron-based Family of High TC Magnetic Superconductors
• Strong coupling between magnetic and structural order parameters in SrFe2As2
• Lattice and Magnetic structures of PrFeAsO, PrFeAsO0.85F0.15 and PrFeAsO0.85
• Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Interplay between magnetism and superconductivity in Fe-pnictides
• High energy spin excitations in BaFe2As2
• Influence of the rare-earth element on the effects of the structural and magnetic phase transitions in CeFeAsO, PrFeAsO, and NdFeAsO
• Valley density-wave and multiband superconductivity in Fe-pnictides
• A Generic Two-band Model for Unconventional Superconductivity and Spin-Density-Wave Order in Electron and Hole Doped Iron-Based Superconductors
• Quantum oscillations in the parent pnictide BaFe${}_2$As${}_2$ : itinerant electrons in the reconstructed state
• Competing orders in FeAs layers
• Anisotropic three-dimensional magnetism in CaFe2As2
• ARPES studies of the electronic structure of LaOFe(P,As)
• Magnetic and Metallic State at Intermediate Hubbard U Coupling in Multiorbital Models for Undoped Fe Pnictides
• Pnictides as frustrated quantum antiferromagnet close to a quantum phase transition
• On the electronic structure of electron doped LaOFeAs as seen by X-ray absorption spectroscopy
• Excitonic spin density wave state in iron pnictides
• Thermodynamic properties of Ba1-xMxFe2As2 (M = La and K)

Cited by in corpus (15)

• Low-energy microscopic models for iron-based superconductors: a review
• Theory of itinerant magnetic excitations in the SDW phase of iron-based superconductors
• Spin and Charge Dynamics Ruled by Antiferromagnetic Order in Iron Pnictides
• Superconductivity in high-$T_c$ and related strongly correlated systems from variational perspective: Beyond mean field theory
• Magnetic order in orbital models of the iron pnictides
• Spin excitations in the nematic phase and the metallic stripe spin-density wave phase of iron pnictides
• Impact of Dynamic Orbital Correlations on Magnetic Excitations in the Normal State of Iron-Based Superconductors
• Electric and magnetic multipoles and bond orders in excitonic insulators
• Low-energy excitation spectra in the excitonic phase of cobalt oxides
• Collective magnetic excitations of $C_4$ symmetric magnetic states in iron-based superconductors
• Distortional weak-coupling instability of Bogoliubov Fermi surfaces
• Excitonic Insulator State of the Extended Falicov-Kimball Model in the Cluster Dynamical Impurity Approximation
• Competing phases in a model of Pr-based cobaltites
• Excitonic Instabilities and Insulating States in Bilayer Graphene
• High-Energy Damping by Particle-Hole Excitations in the Spin-Wave Spectrum of Iron-Based Superconductors