Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy.

Abstract

We performed optical spectroscopy measurement on single crystals of BaFe2As2 and SrFe2As2, the parent compounds of FeAs-based superconductors. Both are found to be quite metallic with fairly large plasma frequencies at high temperature. Upon entering the spin-density-wave state, the formation of partial energy gaps was clearly observed with the surprising presence of two different energy scales. A large part of the Drude component was removed by the gapping of Fermi surfaces. Meanwhile, the carrier scattering rate was even more dramatically reduced. We elaborate that the spin-density-wave instability is more likely to be driven by the Fermi surface nesting of itinerant electrons than a local-exchange mechanism.

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Cite this paper

@article{Hu2008OriginOT, title={Origin of the spin density wave instability in AFe2As2 (A=Ba,Sr) as revealed by optical spectroscopy.}, author={Wenbing Hu and Jun Dong and Guang Li and Zhuo Li and Ping Zheng and G . F . Chen and J . L . Luo and N . L . Wang}, journal={Physical review letters}, year={2008}, volume={101 25}, pages={257005} }