Electronic structure of prototype AFe2As2 and ReOFeAs high-temperature superconductors: a comparison
I. A. Nekrasov, Z. V. Pchelkina*, M. V. Sadovskii
Institute for Electrophysics RAS, 620016 Ekaterinburg, Ural Division, Russia
*Institute for Metal Physics RAS, 620041 Ekaterinburg, Ural Division, GSP-170, Russia
PACS: 71.20.-b, 74.25.Jb, 74.70.-b
Abstract
We have performed ab initio LDA calculations of electronic
structure of newly discovered prototype high-temperature superconductors
AFe2As2 (A=Ba,Sr) and compared it with previously calculated
electronic spectra of ReOFeAs (Re=La,Ce,Pr,Nd,Sm).
In all cases we obtain almost identical densities of states in rather wide energy interval
(up to 1 eV) around the Fermi level. Energy dispersions are also very similar
and almost two-dimensional in this energy interval, leading to the same basic
(minimal) model of electronic spectra, determined mainly by Fe
d-orbitals of FeAs layers.
The other constituents, such as A ions or rare earths Re (or oxygen states)
are more or less irrelevant for superconductivity.
LDA Fermi surfaces for AFe2As2 are also very similar to that of
ReOFeAs.
This makes the more simple AFe2As2 a generic system to study
high-temperature superconductivity in FeAs - layered compounds.