Hidden SDW order and effective low-energy theory for FeAs superconductors

Abstract

We propose a simple effective model to describe FeAs superconductors. This model is based on the assumption of a local spin-density-wave (SDW) order, with its magnetization direction allowed to fluctuate. It is shown that the long-range order with momentum Q=(π,π) is generally unstable in competing with the kinetic energy of the charge carriers. A true weak SDW order is formed in the undoped case with an additional momentum shift Q_s=(π, 0) due to the peculiar Fermi surface nesting. In the doped case, the unstable long-range order driven by kinetic energy can naturally result in a d-wave superconducting condensation. Such low-energy physics is protected by the presence of the local SDW which sustains some kind of "Mott gags" for the multiband d-electrons near the Fermi energy.

5 pages, 2 figures; some typos are corrected and minor changes are made

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Cited by in corpus (4)

• Electronic and lattice dynamical properties of the iron-based superconductors LiFeAs and NaFeAs
• Investigation of Superconducting Gap Structure in TbFeAsO${}_{0.9}$F${}_{0.1}$ using Point Contact Andreev Reflection
• Vortex state in iron-based superconductors with collinear antiferromagnetic cores
• Scanning tunneling microscopy of the 32 K superconductor (Sr1-xKx)Fe2As2