Yu, RongHu, HaoyuNica, Emilian M.Zhu, Jian-XinSi, Qimiao2021-06-102021-06-102021Yu, Rong, Hu, Haoyu, Nica, Emilian M., et al.. "Orbital Selectivity in Electron Correlations and Superconducting Pairing of Iron-Based Superconductors." <i>Frontiers in Physics,</i> 9, (2021) Frontiers Media S.A.: https://doi.org/10.3389/fphy.2021.578347.https://hdl.handle.net/1911/110717Electron correlations play a central role in iron-based superconductors. In these systems, multiple Fe $3d$-orbitals are active in the low-energy physics, and they are not all degenerate. For these reasons, the role of orbital-selective correlations has been an active topic in the study of the iron-based systems. In this paper, we survey the recent developments on the subject. For the normal state, we emphasize the orbital-selective Mott physics that has been extensively studied, especially in the iron chalcogenides, in the case of electron filling $n \sim 6$. In addition, the interplay between orbital selectivity and electronic nematicity is addressed. For the superconducting state, we summarize the initial ideas for orbital-selective pairing, and discuss the recent explosive activities along this direction. We close with some perspectives on several emerging topics. These include the evolution of the orbital-selective correlations, magnetic and nematic orders and superconductivity as the electron filling factor is reduced from $6$ to $5$, as well as the interplay between electron correlations and topological bandstructure in iron-based superconductors.engThis is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.Journal articlefphy-09-578347https://doi.org/10.3389/fphy.2021.578347