Department of Physics and Astronomy, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada.
Leibniz Institute for Solid State and Materials Research IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.
Science. 2016 Feb 5;351(6273):576-8. doi: 10.1126/science.aad1824.
In underdoped cuprate superconductors, a rich competition occurs between superconductivity and charge density wave (CDW) order. Whether rotational symmetry-breaking (nematicity) occurs intrinsically and generically or as a consequence of other orders is under debate. Here, we employ resonant x-ray scattering in stripe-ordered superconductors (La,M)2CuO4 to probe the relationship between electronic nematicity of the Cu 3d orbitals, structure of the (La,M)2O2 layers, and CDW order. We find distinct temperature dependences for the structure of the (La,M)2O2 layers and the electronic nematicity of the CuO2 planes, with only the latter being enhanced by the onset of CDW order. These results identify electronic nematicity as an order parameter that is distinct from a purely structural order parameter in underdoped striped cuprates.
在欠掺杂铜酸盐超导体中，超导性和电荷密度波（CDW）有序之间存在着丰富的竞争。旋转对称性破缺（向列性）是内在的和普遍存在的，还是其他序的结果，这是一个有争议的问题。在这里，我们在条纹有序超导体（La,M）2CuO4 中采用共振 X 射线散射来探测 Cu 3d 轨道的电子向列性、（La,M）2O2 层的结构和 CDW 有序之间的关系。我们发现（La,M）2O2 层的结构和 CuO2 平面的电子向列性具有明显的温度依赖性，只有后者随着 CDW 有序的出现而增强。这些结果表明，电子向列性是一个不同于欠掺杂条纹铜酸盐中纯结构有序参数的有序参数。
