Is BaCr${}_2$As${}_2$ symmetrical to BaFe${}_2$As${}_2$ with respect to half $3d$ shell filling?

Abstract

We have performed an angle-resolved photoemission spectroscopy study of BaCr${}_2$As${}_2$, which has the same crystal structure as BaFe${}_2$As${}_2$, a parent compound of Fe-based superconductors. We determine the Fermi surface of this material and its band dispersion over 5 eV of binding energy. Very moderate band renormalization (1.35) is observed for only two bands. We attribute this small renormalization to enhanced direct exchange as compared to Fe in BaFe${}_2$As${}_2$, and to a larger contribution of the $e_g$ orbitals in the composition of the bands forming the Fermi surface, leading to an effective valence count that is reduced by Fe $d$ - As $p$ hybridization.

Extended discussion. 6 pages, 4 figures. This is authors version. The published version can be found at https://journals.aps.org/prb/