发表机构
University of Oxford; Laboratoire National des Champs Magnetiques Intenses, EMFL, CNRS, Univ. Grenoble Alpes, INSA-T, Univ. Toulouse 3; National High Magnetic Field Laboratory and Department of Physics, Florida State University; Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology（牛津大学; 法国国家强磁场实验室; 佛罗里达州立大学; 卡尔斯鲁厄理工学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
该研究在高达68特斯拉磁场下于FeSe$_{1-x}$S$_x$向列相内发现场致自旋密度波相，通过输运与量子振荡证据表明，减弱向列性可稳定SDW序并促进超导配对机制。
AI 中文摘要
自旋密度波（SDW）序与超导性在非常规超导体中经常相互竞争并共存，其中自旋涨落常常介导超导配对。在铁硫族超导体 FeSe$_{1-x}$S$_x$ 中，SDW 序仅在施加压力下被探测到，而自旋涨落和向列涨落共同决定了其丰富的超导相图。在此，我们报告了在高达 68~T 的磁场下，FeSe$_{1-x}$S$_x$ 向列态内出现初始 SDW 相的证据。一旦超导被抑制，我们观察到纵向电阻率的急剧上升，并伴随隧道二极管振荡器频率响应和扭矩各向异性的异常，这与场致电子序一致。占主导地位的低频量子振荡揭示了一个小的重构费米面，与场致 SDW 序一致。与压力调控的向列类似物 FeSe$_{0.96}$S$_{0.04}$ 的直接实验比较表明，通过化学替代和施加压力，SDW 相在 FeSe$_{1-x}$S$_x$ 的向列相内均得以稳定。这些发现揭示，通过减弱向列性，SDW 序得以稳定，从而促进了铁硫族化合物中占主导的超导配对机制。
英文摘要
Spin-density wave (SDW) order and superconductivity frequently compete and coexist in unconventional superconductors, where spin fluctuations often mediate superconducting pairing. In iron-chalcogenide superconductors, FeSe$_{1-x}$S$_x$, SDW order has only been detected under applied pressure, while both spin and nematic fluctuations are involved in determining their rich superconducting phase diagrams. Here, we report evidence for an incipient SDW phase, within the nematic state of FeSe$_{1-x}$S$_x$, revealed in magnetic fields up to 68~T. Once superconductivity is quenched, we observe sharp upturns in longitudinal resistivity accompanied by anomalies in tunnel diode oscillator frequency response and torque anisotropy, consistent with a field-induced electronic order. Dominant low-frequency quantum oscillations reveal a small reconstructed Fermi surface, consistent with a field-induced SDW order. Direct experimental comparisons with a pressure-tuned nematic, analogue, FeSe$_{0.96}$S$_{0.04}$, demonstrate that SDW phases are stabilized within the nematic phase of FeSe$_{1-x}$S$_x$ via both chemical substitution and applied pressure. These findings reveal that by weakening nematicity, the SDW orders are stabilised, which promotes the dominant superconducting pairing mechanism in iron chalcogenides.
Comments10 pages, 4 figures
