Dresden 2009 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 36: Focussed Session: Superconductivity and Magnetism in Ferropnictides and Related Materials
TT 36.6: Topical Talk
Thursday, March 26, 2009, 12:00–12:30, HSZ 03
Quasiparticle renormalization effects in the normal-state optical properties of iron pnictides — •Alexander Boris1, N.N. Kovaleva1,2, P. Popovich1, Y. Matiks1, C.T. Lin1, R.K. Kremer1, L. Boeri1, O.V. Dolgov1, I.I. Mazin3, and B. Keimer1 — 1Max-Planck-Institut für Festkörperforschung, 70569 Stuttgart — 2Department of Physics, Loughborough University, Loughborough, United Kingdom — 3CCMS, Naval Research Laboratory, Washington, D.C. 20375, USA
We report a comprehensive spectroscopic ellipsometry study on iron pnictides, LaFeAsO1−xFx and Sr1−xKxFe2As2, over a wide range of temperatures (10 - 350 K) and photon energies extending from the far infrared (IR) into the deep ultraviolet (UV), 0.01 - 6.5 eV. The optical conductivity spectra are dominated by a sequence of interband transitions which agree very well with those predicted by LDA calculations. The free charge carrier response is, however, heavily damped. This implies that the electronic states near the Fermi surface are strongly renormalized. From our optical measurements we address
i) electron-electron correlation effects [1],
ii) electron-phonon coupling, and
iii) dynamic charge and spin ordering [2]
as possible renormalization factors.
[1] A.V.Boris et al., preprint at arXiv:0806.1732;
[2] I.I. Mazin and M.D. Johannes, Nature Physics (in press), preprint at arXiv:0807.3737.