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

Zheng-Yu Weng

doi:10.1016/j.physe.2009.02.015

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arXiv · 0804.3228

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

Zheng-Yu Weng

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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.

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Zheng-Yu Weng. 2008-04-27. Hidden SDW order and effective low-energy theory for FeAs superconductors. https://doi.org/10.1016/j.physe.2009.02.015

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