Electronic Band Structure of BaCo2As2: A Fully Doped Ferropnictide Analog with Reduced Electronic Correlations

We report an investigation with angle-resolved photoemission spectroscopy of the Fermi surface and electronic band structure of BaCo2As2. Although its quasinesting-free Fermi surface differs drastically from that of its Fe-pnictide cousins, we show that the BaCo2As2 system can be used as an approximation to the bare unoccupied band structure of the related BaFe2-xCoxAs2 and Ba1-xKxFe2As2 compounds. However, our experimental results, in agreement with dynamical-mean-field-theory calculations, indicate that electronic correlations are much less important in BaCo2As2 than in the ferropnictides. Our findings suggest that this effect is due to the increased filling of the electronic 3d shell in the presence of significant Hund's exchange coupling. DOI: 10.1103/PhysRevX.3.011006