Transport evidence for decoupled nematic and magnetic criticality in iron chalcogenides
Transport evidence for decoupled nematic and magnetic criticality in iron chalcogenides
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DOI：
10.1038/s42005-022-00873-8
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发表时间：
2022-04-22
影响因子：
5.5
通讯作者：
Hussey, Nigel E.
中科院分区：
文献类型：
--
作者：
Ayres, Jake;Culo, Matija;Hussey, Nigel E.
相关金属中的电子向列性经常伴随着另一种不稳定性，例如磁性。因此，问题仍然是，单单向列性是否能够驱动此类系统中的非常规超导电性或反常(量子临界)输运。在FeSe，线虫孤立地出现，为解决这个问题提供了一个独特的机会。然而，到目前为止的研究被证明是不确定的；虽然在硫代换时观察到向列相临界性的迹象，但它们似乎被压力下的浮现磁性所熄灭。在这里，我们研究了FeSe1-xSx晶体在x值超过向列相量子临界点时的低温电阻率与温度和压力的关系。揭示了电阻率的两个截然不同的成分；一个随着压力的增加而被抑制，另一个在更高的压力下接近磁态时增长。这些发现表明，FeSe1-xSx中的向列相和磁临界涨落是完全不耦合的，这与其他铁基超导体形成鲜明对比。对于向列相和磁涨落在铁基超导体非常规超导电性表现中所起的作用，目前还没有明确的共识。在这里，作者研究了硫掺杂的FeSe在外加压力下的电阻性质，发现了对电阻率有两个不同贡献的证据，这表明在这个系统中向列相和磁涨落是解耦的。
Electronic nematicity in correlated metals often occurs alongside another instability such as magnetism. The question thus remains whether nematicity alone can drive unconventional superconductivity or anomalous (quantum critical) transport in such systems. In FeSe, nematicity emerges in isolation, providing a unique opportunity to address this question. Studies to date, however, have proved inconclusive; while signatures of nematic criticality are observed upon sulfur substitution, they appear to be quenched by the emergent magnetism under the application of pressure. Here, we study the temperature and pressure dependence of the low-temperature resistivity of FeSe1-xSx crystals at x values beyond the nematic quantum critical point. Two distinct components to the resistivity are revealed; one that is suppressed with increasing pressure and one that grows upon approaching the magnetic state at higher pressures. These findings hint that nematic and magnetic critical fluctuations in FeSe1-xSx are completely decoupled, in marked contrast to other Fe-based superconductors.The role nematicity and magnetic fluctuations play in the manifestation of unconventional superconductivity for Fe-based superconductors is actively debated with, so far, no clear consensus. Here, the authors study the resistive properties of sulfur-doped FeSe under applied pressure finding evidence of two distinct contributions to the electrical resistivity, which suggest a decoupling of nematic and magnetic fluctuations in this system.