Lake B, Rønnow H M, Christensen N B, Aeppli G, Lefmann K, McMorrow D F, Vorderwisch P, Smeibidl P, Mangkorntong N, Sasagawa T, Nohara M, Takagi H, Mason T E
Oak Ridge National Laboratory, PO Box 2008 MS 6430, Oak Ridge, Tennessee 37831-6430, USA.
Nature. 2002 Jan 17;415(6869):299-302. doi: 10.1038/415299a.
One view of the high-transition-temperature (high-Tc) copper oxide superconductors is that they are conventional superconductors where the pairing occurs between weakly interacting quasiparticles (corresponding to the electrons in ordinary metals), although the theory has to be pushed to its limit. An alternative view is that the electrons organize into collective textures (for example, charge and spin stripes) which cannot be 'mapped' onto the electrons in ordinary metals. Understanding the properties of the material would then need quantum field theories of objects such as textures and strings, rather than point-like electrons. In an external magnetic field, magnetic flux penetrates type II superconductors via vortices, each carrying one flux quantum. The vortices form lattices of resistive material embedded in the non-resistive superconductor, and can reveal the nature of the ground state-for example, a conventional metal or an ordered, striped phase-which would have appeared had superconductivity not intervened, and which provides the best starting point for a pairing theory. Here we report that for one high-Tc superconductor, the applied field that imposes the vortex lattice also induces 'striped' antiferromagnetic order. Ordinary quasiparticle models can account for neither the strength of the order nor the nearly field-independent antiferromagnetic transition temperature observed in our measurements.
对于高温转变温度（高温超导）铜氧化物超导体的一种观点认为，它们是传统超导体，配对发生在弱相互作用的准粒子（对应于普通金属中的电子）之间，尽管该理论必须被推到极限。另一种观点是，电子组织成集体结构（例如电荷和自旋条纹），这些结构无法“映射”到普通金属中的电子上。那么，理解这种材料的性质就需要诸如结构和弦等物体的量子场论，而不是点状电子的量子场论。在外部磁场中，磁通量通过涡旋穿透II型超导体，每个涡旋携带一个磁通量子。涡旋形成嵌入非电阻性超导体中的电阻性材料晶格，并能揭示基态的性质——例如，一种传统金属或有序条纹相——如果没有超导介入，这种相本来会出现，并且它为配对理论提供了最佳起点。在此，我们报告，对于一种高温超导超导体，施加涡旋晶格的外加磁场也会诱导出“条纹状”反铁磁序。普通准粒子模型既无法解释该序的强度，也无法解释我们测量中观察到的几乎与磁场无关的反铁磁转变温度。
