Ding Qing-Ping, Schmidt Juan, Moreno Jose A, Bud'ko Sergey L, Canfield Paul C, Furukawa Yuji
Ames National Laboratory, U.S. DOE, Ames, Iowa 50011, USA.
Iowa State University, Department of Physics and Astronomy, Ames, Iowa 50011, USA.
Phys Rev Lett. 2025 Jun 6;134(22):226002. doi: 10.1103/kxth-gxvm.
The relationship between antiferromagnetic (AFM) spin fluctuations (SF), nematic fluctuations, and superconductivity (SC) has been central to understanding the pairing mechanism in iron-based superconductors (IBSCs). Iron chalcogenides, which hold the simplest crystal structure in IBSCs, provide a good platform to investigate the relationship. Here, we report ^{77}Se and ^{125}Te nuclear magnetic resonance studies of FeSe_{0.47}Te_{0.53}, which is located close to a nematic quantum critical point (QCP), under pressures up to 1.35 GPa. Both the superconducting critical temperature and AFMSF were found to be enhanced under pressure, which suggests a correlation between SC and AFMSF in FeSe_{0.47}Te_{0.53}. However, the contribution of AFMSF to SC in FeSe_{0.47}Te_{0.53} was found to be much less compared to that in FeSe_{1-x}S_{x}, suggesting that nematic fluctuations play a dominant role in the SC in FeSe_{1-x}Te_{x} around the nematic QCP.
反铁磁（AFM）自旋涨落（SF）、向列涨落与超导（SC）之间的关系一直是理解铁基超导体（IBSCs）配对机制的核心。铁硫族化合物在IBSCs中具有最简单的晶体结构，为研究这种关系提供了一个良好的平台。在此，我们报告了在高达1.35 GPa的压力下，对接近向列量子临界点（QCP）的FeSe_{0.47}Te_{0.53}进行的^{77}Se和^{125}Te核磁共振研究。发现超导临界温度和AFM SF在压力下均增强，这表明在FeSe_{0.47}Te_{0.53}中SC与AFM SF之间存在关联。然而，与FeSe_{1-x}S_{x}相比，发现AFM SF对FeSe_{0.47}Te_{0.53}中SC的贡献要小得多，这表明向列涨落在向列QCP附近的FeSe_{1-x}Te_{x}的SC中起主导作用。
