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VOLUME 97 (2013) | ISSUE 1 |
PAGE 18
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LDA +DMFT investigation of electronic structure of K 1-xFe 2-ySe 2 superconductor
I. A. Nekrasov+, N. S. Pavlov+, M. V. Sadovskii+*
+Institute for Electrophysics UB RAS, 620016 Ekaterinburg, Russia *Institute for Metal Physics UB RAS 620990 Ekaterinburg, Russia
Abstract
We investigate electronic structure of the new iron chalcogenide
high temperature superconductor K1-xFe2-ySe2 (hole doped
case with x=0.24, y=0.28) in the normal phase using the novel
LDA+DMFT computational approach.
We show that this iron chalcogenide is more correlated
in a sense of bandwidth renormalization (energy scale compression
by factor about 5 in the interval 1.5 eV), than typical iron pnictides
(compression factor about 2), though the Coulomb interaction strength is
almost the same in both families. Our results for spectral densities are in
general agreement with recent ARPES data on this system. It is found that all
Fe-3d(t2g) bands crossing the Fermi level have equal renormalization, in
contrast to some previous interpretations. Electronic states at the Fermi
level are of predominantly xy symmetry. Also we show that LDA+DMFT
results are in better agreement with experimental spectral function maps,
than the results of conventional LDA+DMFT. Finally we make predictions for
photoemission spectra lineshape for K0.76Fe1.72Se2 .
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