  Understanding the Fermi surface and low-energy excitations of iron or cobalt
pnictides is crucial for assessing electronic instabilities such as magnetic or
superconducting states. Here, we propose and implement a new approach to
compute the low-energy properties of correlated electron materials, taking into
account both screened exchange beyond the local density approximation and local
dynamical correlations. The scheme allows us to resolve the puzzle of BaCo2As2,
for which standard electronic structure techniques predict a ferromagnetic
instability not observed in nature.
