Pressure-induced phenomena and physics in iron-based superconductors

The discovery of Fe-based superconductor in 2018 opened an illustrious chapter in the history of high temperature superconductors. Over the past ten years, many progresses on experiments, theories and applications have been achieved in the studies of Fe-based superconductors, which have greatly enriched the basic knowledge on the superconductivity of high temperature (Tc) superconductors and laid a solid foundation for uncovering superconducting mechanism of high-Tc superconductors and expanding their applications. In this review article, we present some important progresses and new phenomena/physics exhibited in the pressurized Fe-based superconductors, including pressure-induced superconductivity, pressure-induced reemergence of superconductivity, pressure-enhanced superconducting temperature, the prediction on the highest superconducting temperature for Fe-based superconductors via high pressure studies, the effect of the separated phase structure on the superconductivity and the discovery of a bi-critical point between antiferromagnetic and superconducting phases. It is expected that these high pressure experimental results on Fe-based superconductors, together with the results reported in the same issue through other experimental and theoretical methods, can aid to outline a more complete physical picture for a more comprehensive and deeper understanding on Fe-based superconductors.