1210.5576 (N. Xu et al.)

Electronic band structure of BaCo$_{2}$As$_2$: a fully-doped
ferropnictide with reduced electronic correlations    [PDF]

N. Xu, P. Richard, A. van Roekeghem, P. Zhang, H. Miao, W. -L. Zhang, T. Qian, M. Ferrero, A. S. Sefat, S. Biermann, H. Ding

We report an angle-resolved photoemission spectroscopy investigation of the Fermi surface and electronic band structure of BaCo$_{2}$As$_2$. Although its quasi-nesting-free Fermi surface differs drastically from that of its Fe-pnictide cousins, we show that the BaCo$_{2}$As$_2$ system can be used as an approximation to the bare unoccupied band structure of the related BaFe$_{2-x}$Co$_x$As$_2$ and Ba$_{1-x}$K$_x$Fe$_2$As$_2$ compounds. However, our experimental results, in agreement with dynamical mean field theory calculations, indicate that electronic correlations are much less important in BaCo$_{2}$As$_2$ than in the ferropnictides. Our findings suggest that this effect is due to the increased filling of the electronic 3$d$ shell in the presence of significant Hund's exchange coupling.

View original: http://arxiv.org/abs/1210.5576