Competing orders, short-time dynamics and BCS-BEC crossover in iron-based superconductors.

The discovery of superconductivity in Fe-based superconductors in 2008 with Tc reaching almost 80K is among the most significant breakthroughs in contemporary condensed matter physics. The experimental data on superconductivity show rich behavior, with potentially different symmetry of a superconducting state for different compositions of the same material. Furthermore, the phase diagram reveal a complex interplay between magnetism and superconductivity typical for other exotic superconductors such as cuprates or heavy fermions. In my talk I will discuss the physics of the phase diagram and argue that all pairing states obtained so far can be understood within the same universal pairing scenario. Furthermore, I will review the recent development of the field related to the use of STM as a phase sensitive probe, time-reversal symmetry broken states, and the short-time dynamics behavior of iron-based superconductors expected in the pump-probe spectroscopy.