Relationship Between Nematicity, Antiferromagnetic Fluctuations, and Superconductivity in FeSe1-xSx Revealed by NMR

The S-substituted FeSe, FeSe1-xSx, under pressure (p), provides a versatile platform for studying the relationship among nematicity, antiferromagnetism, and superconductivity. Here we present a short review of the recent experimental evidence showing that nematicity has a remarkable impact on the relationship between antiferromagnetic fluctuations and superconductivity. This has been revealed by several Se-77 nuclear magnetic resonance studies that have tracked the variability of antiferromagnetic fluctuations and superconducting transition temperature (T-c) as a function of x and p. T-c is roughly proportional to antiferromagnetic fluctuations in the presence or absence of nematic order suggesting the importance of antiferromagnetic fluctuations in the Cooper pairing mechanism in FeSe1-xSx. However, the antiferromagnetic fluctuations are more effective in enhancing superconductivity in the absence of nematicity as compared to when it is present. These experimental observations give renewed insights into the interrelationships between nematicity, magnetism, and superconductivity in Fe-based superconductors.

Automated summary

This review discusses the impact of nematicity on the relationship between antiferromagnetic fluctuations and superconductivity in the S-substituted FeSe, FeSe1-xSx, system. Experimental evidence shows that antiferromagnetic fluctuations play a crucial role in the Cooper pairing mechanism and the superconducting transition temperature (Tc) is roughly proportional to the fluctuations. However, the presence of nematicity weakens the effectiveness of antiferromagnetic fluctuations in enhancing superconductivity.