Ab-initio perspective on structural and electronic properties of iron-based superconductors

The discovery of iron pnictides and iron chalcogenides as a new class of unconventional superconductors in 2008 has generated an enourmous amount of experimental and theoretical work that identifies these materials as correlated metals with multiorbital physics, where magnetism, nematicity and superconductivity are competing phases that appear as a function of pressure and doping. A microscopic understanding of the appearance of these phases is crucial in order to determine the nature of superconductivity in these systems. Here we review our recent theoretical efforts to describe and understand from first principles the properties of iron pnictides and chalcogenides with special focus on (i) pressure dependence, (ii) effects of electronic correlation and (iii) origin of magnetism and superconductivity.