Institut für Physik, BTU Cottbus-Senftenberg, PBox 101344, 03013 Cottbus, Germany.
ISC-CNR, CNISM and Dipartimento di Fisica, Università di Roma "La Sapienza", P.le Aldo Moro 5, I-00185 Roma, Italy.
Sci Rep. 2014 Jun 17;4:5319. doi: 10.1038/srep05319.
High-temperature superconductors exhibit a characteristic hourglass-shaped spectrum of magnetic fluctuations which most likely contribute to the pairing glue in the cuprates. Recent neutron scattering experiments in strongly underdoped compounds have revealed a significant low energy anisotropy of these fluctuations which we explain by a model in which topological defects of the antiferromagnet clump to producing domain wall segments with ferronematic order. This state does not invoke global charge order but breaks C4 rotational and inversion symmetry. The incommensurability of the low doping charge-disordered state is in good agreement with experiment and interpolates smoothly with the incommensurability of the stripe phase at higher doping. Within linear spin-wave theory the dynamic structure factor is in very good agreement with inelastic neutron scattering data and can account for the observed energy dependent anisotropy.
高温超导体表现出一种特征性的沙漏状磁涨落能谱，这种能谱很可能对铜氧化物中的配对胶结贡献良多。最近在强欠掺杂化合物中的中子散射实验揭示了这些涨落具有显著的低能各向异性，我们通过一个模型来解释这种各向异性，该模型认为反铁磁体的拓扑缺陷聚集在一起形成具有亚铁磁序的畴壁段。这种状态不涉及全局电荷有序，但会破坏 C4 旋转和反演对称。低掺杂电荷无序态的非调谐性与实验很好地吻合，并与较高掺杂时条纹相的非调谐性平滑地插值。在线性自旋波理论中，动态结构因子与非弹性中子散射数据非常吻合，可以解释观察到的能量相关各向异性。
