Superconducting spin smecticity evidencing the Fulde-Ferrell-Larkin-Ovchinnikov state in Sr2RuO4
Superconducting spin smecticity evidencing the Fulde-Ferrell-Larkin-Ovchinnikov state in Sr2RuO4
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DOI：
10.1126/science.abb0332
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发表时间：
2022-04-22
期刊：
影响因子：
56.9
通讯作者：
Ishida, K.
中科院分区：
文献类型：
--
作者：
Kinjo, K.;Manago, M.;Ishida, K.
平移对称破缺与静态流动性相反，但可以在超导体中实现，超导体中包含由电子对形成的量子力学相干流体。这种状态的一个特殊例子是Fulde-Ferrell-Larkin-Ovchinnikov(FFLO)态，它是由施加在自旋单态超导体上的时间反转对称破缺磁场引起的。这种状态本质上伴随着超导的自旋近度、自旋密度调制的流体和自发的平移对称性破缺。对这种自旋近密度的检测为FFLO状态提供了明确的证据，但它的观察一直具有挑战性。在此，我们报道了层状超导体Sr2RuO4在其上临界场附近的“双喇叭”核磁共振特征谱，表明自旋密度的空间正弦调制与超导的自旋近密度是一致的。我们的工作表明，Sr2RuO4为研究FFLO物理提供了一个通用的平台。
Translational symmetry breaking is antagonistic to static fluidity but can be realized in superconductors, which host a quantum-mechanical coherent fluid formed by electron pairs. A peculiar example of such a state is the Fulde-Ferrell-Larkin-Ovchinnikov (FFLO) state, induced by a time-reversal symmetry-breaking magnetic field applied to spin-singlet superconductors. This state is intrinsically accompanied by the superconducting spin smecticity, spin density-modulated fluidity with spontaneous translational-symmetry breaking. Detection of such spin smecticity provides unambiguous evidence for the FFLO state, but its observation has been challenging. Here, we report the characteristic "double-horn" nuclear magnetic resonance spectrum in the layered superconductor Sr2RuO4 near its upper critical field, indicating the spatial sinusoidal modulation of spin density that is consistent with superconducting spin smecticity. Our work reveals that Sr2RuO4 provides a versatile platform for studying FFLO physics.