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High-temperature superconductivity in iron pnictides and chalcogenides

Abstract

Superconductivity develops in metals upon the formation of a coherent macroscopic quantum state of electron pairs. Iron pnictides and chalcogenides are materials that have high superconducting transition temperatures. In this Review, we describe the advances in the field that have led to higher superconducting transition temperatures in iron-based superconductors and the wide range of materials that are used to form these superconductors. We summarize the essential aspects of the normal state and the mechanism for superconductivity. We emphasize the degree of electron–electron correlations and their manifestation in properties of the normal state. We examine the nature of magnetism, analyse its role in driving the electronic nematicity and discuss quantum criticality at the border of magnetism in the phase diagram. Finally, we review the amplitude and structure of the superconducting pairing, and survey the potential material settings for optimizing superconductivity.

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Figure 1: Materials characteristics of iron-based superconductors.
Figure 2: Bad-metal behaviour and electron correlations.
Figure 3: Magnetism in the iron pnictides.
Figure 4: Magnetism in iron chalcogenides.
Figure 5: Quantum criticality in iron pnictides.
Figure 6: Superconductivity in iron pnictides and chalcogenides.

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Acknowledgements

The authors thank J. Analytis, M. Bendele, P. C. Dai, W. Ding, L. Harriger, X. Lu and P. Nikolic for their input. They have benefited from collaborations and/or discussions with J. Dai, P. C. Dai, W. Ding, P. Goswami, K. Grube, D. H. Lu, A. H. Nevidomskyy, E. Nica, P. Nikolic, Z.-X. Shen, H. von Löhneysen, Z. Wang, M. Yi, and J.-X. Zhu. This work was supported in part by the NSF (grant number DMR-1309531) and the Robert A. Welch Foundation (grant number C-1411) (Q.S.), and by the National Science Foundation of China (grant number 11374361) and the Fundamental Research Funds for the Central Universities and the Research Funds of Renmin University of China (R.Y.). They acknowledge the support provided in part by the NSF (grant number. NSF PHY11-25915) at KITP, UCSB, for our participation in the autumn 2014 programme on “Magnetism, Bad Metals and Superconductivity: Iron Pnictides and Beyond”. Q.S. and E.A. acknowledge the hospitality of the Aspen Center for Physics (NSF grant number 1066293).

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Si, Q., Yu, R. & Abrahams, E. High-temperature superconductivity in iron pnictides and chalcogenides. Nat Rev Mater 1, 16017 (2016). https://doi.org/10.1038/natrevmats.2016.17

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