Magnetism and Superconductivity in Iron-based Superconductors Decided by Condensed Particle-hole Excitations away from the Fermi Level

Abstract

The origin of magnetism and superconductivity in iron-based superconductors is still unclear. Here, by investigating the momentum-dependent particle-hole excitations which quantify the tendency of itinerant electrons towards various magnetic states or superconducting phases, we unravel a novel origin to account for the variety of physical properties of iron-based compounds. We show that condensation of particle-hole excitations away from the Fermi surface in momentum space is the underlying mechanism in deciding the magnetic and superconducting properties of iron-based materials. The applicability of this scenario to the whole family of iron-based superconductors suggests that inclusion of the orbital degrees of freedom, which may lead to competing tendencies towards different magnetically ordered states, is more crucial than taking into account the strong correlations. Our findings further indicate that in order to properly model these materials, the electronic states away from the Fermi level have to be considered.

10 pages, 6 figures

References in corpus (10)

• High-temperature superconductivity in iron-based materials
• Magnetic order in BaFe2As2, the parent compound of the FeAs based superconductors in a new structural family
• Magnetism and its microscopic origin in iron-based high-temperature superconductors
• A Sharp Peak of the Zero-Temperature Penetration Depth at Optimal Composition in BaFe2(As1-xPx)2
• Structural and magnetic phase transitions in the ternary iron arsenides SrFe2As2 and EuFe2As2
• Observation of Temperature-Induced Crossover to an Orbital-Selective Mott Phase in A${}_x$Fe${}_{2-y}$Se${}_2$ (A=K, Rb) Superconductors
• Spin and Lattice Structure of Single Crystal SrFe2As2
• Unified Picture for Magnetic Correlations in Iron-Based Superconductors
• Competing orders in FeAs layers
• Low magnetization and anisotropy in the antiferromagnetic state of undoped iron pnictides