Multiorbital Effects on Antiferromagnetism in Fe Pnictides

Abstract

We apply a Hartree-Fock approximation to a two-orbital model proposed for Fe pnictide superconductors. It is found that the antiferromagnetic (AFM) order with the ordering vector Q=(pi,0) is realized. The AFM order appears simultaneously with ferro-orbital order, the latter leads to a secondary lattice distortion. We also investigate the influence of doping on the AFM order. The size of the AFM moment changes continuously for lightly doped cases, but when the amount of doped carriers exceeds a certain value the AFM state is suddenly destroyed. We also show that Fermi surfaces remain and change significantly on doping even in the AFM state. This behaviour is explained by considering the nesting due to the multi-sheet Fermi-surface structure and multiorbital nature of the electronic bands characteristic to Fe pnictides.

5 pages, 4 figures

References in corpus (21)

• 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
• Spin density wave anomaly at 140 K in the ternary iron arsenide BaFe2As2
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Superconductivity up to 37 K in (A1-xSrx)Fe2As2 with A=K and Cs
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Thorium-doping induced superconductivity up to 56 K in Gd1-xThxFeAsO
• Origin of the ~150 K Anomaly in LaOFeAs; Competing Antiferromagnetic Superexchange Interactions, Frustration, and Structural Phase Transition
• Determination of the phase diagram of the electron doped superconductor Ba(Fe${}_{1-x}$Co${}_x$)${}_2$As${}_2$
• Electronic Structure and Doping in BaFe${}_2$As${}_2$ and LiFeAs: Density Functional Calculations
• Superconductivity and Crystal Structures of (Ba1-xKx)Fe2As2 (x = 0 - 1)
• Commensurate Spin Density Wave in LaOFeAs: A Local Probe Study
• Nodal Spin Density Wave and band topology of the FeAs based materials
• Doping-dependent Phase Diagram of LaO{\it M}As ({\it M}=V--Cu) and Electron-type Superconductivity near Ferromagnetic Instability
• Spin and Lattice Structure of Single Crystal SrFe2As2
• Fermi surface of superconducting LaFePO determined by quantum oscillations
• Strong coupling between magnetic and structural order parameters in SrFe2As2
• Spin Ordering in LaOFeAs and Its Suppression in Superconductor LaO0.89F0.11FeAs Probed by Mössbauer Spectroscopy
• Columnar magnetic structure coupled with orthorhombic distortion in the antiferromagnetic iron arsenide SrFe${}_2$As${}_2$