Enhanced Orbital Degeneracy in Momentum Space for LaOFeAs

Abstract

The Fermi surfaces (FS) of LaOFeAs (in $k_z$=0 plane) consist of two hole-type circles around $\Gamma$ point, which do not touch each other, and two electron-type co-centered ellipses around M point, which are degenerate along the M-X line. By first-principles calculations, here we show that additional degeneracy exists for the two electron-type FS, and the crucial role of F-doping and pressure is to enhance this orbital degeneracy. It is suggested that the inter-orbital fluctuation is the key point to understand the unconventional superconductivity in these materials.

4 pages, 5 figures

References in corpus (16)

• Unconventional sign-reversing superconductivity in LaFeAsO_(1-x)F_x
• Superconductivity at 43 K in Samarium-arsenide Oxides $SmFeAs{O}_{1-x}{F}_x$
• 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
• Superconductivity at 41 K and its competition with spin-density-wave instability in layered CeO${}_{1-x}$F${}_x$FeAs
• Competing Orders and Spin-Density-Wave Instability in La(O${}_{1-x}$F${}_x$)FeAs
• Is LaO${}_{1-x}$F${}_x$FeAs an electron-phonon superconductor ?
• Superconductivity at 25 K in hole doped $(L{a}_{1-x}S{r}_x)OFeAs$
• Correlated electronic structure of LaOFeAs
• Doping-dependent Phase Diagram of LaO{\it M}As ({\it M}=V--Cu) and Electron-type Superconductivity near Ferromagnetic Instability
• Upper critical field, Hall effect and magnetoresistance in the iron-based layered superconductor LaFeAsO_{0.9}F_{0.1-δ}
• Hall effect and magnetoresistance in the normal state of the superconductor LaO${}_{0.9}$F${}_{0.1-x}$FeAs
• Superconducting properties of Fe-based layered superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Even Parity, Orbital Singlet and Spin Triplet Pairing for Superconducting $La(O_{1-x}{F}_x)FeAs$
• Point-Contact Spectroscopy of Iron-Based Layered Superconductor LaO${}_{0.9}$F${}_{0.1-\delta }$FeAs
• Pressure Effect on the superconducting properties of LaO_{1-x}F_{x}FeAs(x=0.11) superconductor

Cited by in corpus (20)

• Electronic structure of the iron-based superconductor LaOFeP
• Three orbital model for the iron-based superconductors
• Properties of a two orbital model for oxypnictide superconductors: Magnetic order, B_2g spin-singlet pairing channel, and its nodal structure
• 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
• Orbital Characters Determined from Fermi Surface Intensity Patterns using Angle-Resolved Photoemission Spectroscopy
• Orbital-weight redistribution triggered by spin order in the pnictides
• On interband pairing in multiorbital systems
• Multiorbital Effects on Antiferromagnetism in Fe Pnictides
• High-pressure growth of fluorine-free SmFeAsO${}_{1-x}$ superconducting single crystals
• Evidence for Local Moment by Electron Spin Resonance Study on Polycrystalline LaFeAsO${}_{1-x}$F${}_x$ (x=0 and 0.13)
• Role of Hund's coupling in stabilization of the (0,pi) ordered SDW state within the minimal two-band model for iron pnictides
• Supercell studies of the Fermi surface changes in the electron-doped superconductor LaFeAsO${}_{1-x}$F${}_x$
• Evolution of the Fermi surface topology in doped 122 iron pnictides
• Cooper Pairing in Insulating Valence Band in Fe-Based Superconductors
• Constraints Imposed by Symmetry on Pairing Operators for the Pnictides
• Comment on "Nonmagnetic Impurity Resonances as a Signature of Sign-Reversal Pairing in Fe-As-Based Superconductors"
• Pressure Effects on the Superconducting and Spin-Density-Wave States of the Newly Discovered Sm(O1-xFx)FeAs
• An investigation of the interrelationship between pressure and correlation in LaFeAsO under pressure
• Magneto-orbital coupling in iron pnictides