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

## TL;DR

This study investigates the electronic structure of BaCr$_2$As$_2$ using ARPES, revealing moderate band renormalization and differences from BaFe$_2$As$_2$ related to exchange interactions and orbital contributions.

## Contribution

The paper provides the first detailed ARPES analysis of BaCr$_2$As$_2$, highlighting its electronic similarities and differences with BaFe$_2$As$_2$, especially regarding band renormalization and orbital effects.

## Key findings

- Moderate band renormalization (1.35) observed.
- Enhanced direct exchange compared to BaFe$_2$As$_2$.
- Greater contribution of $e_g$ orbitals affects Fermi surface composition.

## 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.