McMahon Christopher, Achkar A J, da Silva Neto E H, Djianto I, Menard J, He F, Sutarto R, Comin R, Liang Ruixing, Bonn D A, Hardy W N, Damascelli A, Hawthorn D G
Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Quantum Matter Institute, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.
Sci Adv. 2020 Nov 6;6(45). doi: 10.1126/sciadv.aay0345. Print 2020 Nov.
Charge density wave (CDW) order has been shown to compete and coexist with superconductivity in underdoped cuprates. Theoretical proposals for the CDW order include an unconventional -symmetry form factor CDW, evidence for which has emerged from measurements, including resonant soft x-ray scattering (RSXS) in YBaCuO (YBCO). Here, we revisit RSXS measurements of the CDW symmetry in YBCO, using a variation in the measurement geometry to provide enhanced sensitivity to orbital symmetry. We show that the (0 0.31 ) CDW peak measured at the Cu edge is dominated by an form factor rather than a form factor as was reported previously. In addition, by measuring both (0.31 0 ) and (0 0.31 ) peaks, we identify a pronounced difference in the orbital symmetry of the CDW order along the and axes, with the CDW along the axis exhibiting orbital order in addition to charge order.
电荷密度波（CDW）序已被证明在欠掺杂铜酸盐中与超导性相互竞争并共存。CDW序的理论提议包括一种非常规对称性形状因子CDW，其证据已从测量中出现，包括在YBaCuO（YBCO）中的共振软X射线散射（RSXS）。在此，我们重新审视YBCO中CDW对称性的RSXS测量，通过改变测量几何结构以提高对轨道对称性的灵敏度。我们表明，在Cu边缘测量的（0 0.31）CDW峰主要由一种形状因子主导，而不是如先前报道的那种形状因子。此外，通过测量（0.31 0）和（0 0.31）峰，我们确定了CDW序沿a和b轴的轨道对称性存在明显差异，沿a轴的CDW除了电荷序外还表现出轨道序。
