Department of Physics and Astronomy, University of Waterloo, Waterloo N2L 3G1, Canada.
Canadian Light Source, Saskatoon, Saskatchewan S7N 2V3, Canada.
Nat Mater. 2016 Jun;15(6):616-20. doi: 10.1038/nmat4568. Epub 2016 Feb 15.
Recent theories of charge-density-wave (CDW) order in high-temperature superconductors have predicted a primarily d CDW orbital symmetry. Here, we report on the orbital symmetry of CDW order in the canonical cuprate superconductors La1.875Ba0.125CuO4 (LBCO) and YBa2Cu3O6.67 (YBCO), using resonant soft X-ray scattering and a model mapped to the CDW orbital symmetry. From measurements sensitive to the O sublattice, we conclude that LBCO has predominantly s' CDW orbital symmetry, in contrast to the d orbital symmetry recently reported in other cuprates. Furthermore, we show for YBCO that the CDW orbital symmetry differs along the a and b crystal axes and that these both differ from LBCO. This work highlights CDW orbital symmetry as an additional key property that distinguishes the different cuprate families. We discuss how the CDW symmetry may be related to the '1/8-anomaly' and to static spin ordering.
最近关于高温超导体中电荷密度波 (CDW) 序的理论预测了主要的 d 轨道 CDW 对称性。在这里，我们使用共振软 X 射线散射和一个映射到 CDW 轨道对称性的模型，报告了典型铜酸盐超导体 La1.875Ba0.125CuO4 (LBCO) 和 YBa2Cu3O6.67 (YBCO) 中 CDW 序的轨道对称性。从对 O 亚晶格敏感的测量中，我们得出结论，LBCO 具有主要的 s' CDW 轨道对称性，与最近在其他铜酸盐中报道的 d 轨道对称性形成对比。此外，我们还表明 YBCO 中的 CDW 轨道对称性沿 a 和 b 晶轴不同，并且这两者都与 LBCO 不同。这项工作强调了 CDW 轨道对称性作为区分不同铜酸盐家族的另一个关键特性。我们讨论了 CDW 对称性如何与“1/8 异常”和静态自旋有序相关。
