Coupled commensurate charge density wave and lattice distortion in Na 2 Ti 2 P n 2 O ( P n = As , Sb ) determined by x-ray diffraction and angle-resolved photoemission spectroscopy
Coupled commensurate charge density wave and lattice distortion in Na 2 Ti 2 P n 2 O ( P n = As , Sb ) determined by x-ray diffraction and angle-resolved photoemission spectroscopy
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通过 X 射线衍射和角分辨光电子能谱测定 Na 2 Ti 2 P n 2 O ( P n = As , Sb ) 中的耦合相应电荷密度波和晶格畸变
DOI：
10.1103/physrevb.94.104515
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发表时间：
2016
影响因子：
3.7
通讯作者：
Davies N
中科院分区：
文献类型：
--
作者：
Davies N
我们报告单晶X射线衍射测量，揭示了电荷的超结构，出现在密度波过渡之前观察到的散装数据。从结构的精细化，我们建立了相关的失真模式可以描述的两个传播vectorsandwith（Sb）或（As），主要涉及垂直于Ti-O键的Ti原子的面内位移。我们还提出了角度分辨的光电子能谱测量，这表明带折叠和回弯符合密度波具有相同的波矢，并与费米面嵌套，和μ子自旋弛豫数据，这表明没有迹象表明自旋密度波秩序。结果为声子辅助的电荷密度波序提供了直接的证据，并充分表征了一种近似的有序相，这种有序相可以与掺杂的超导电性竞争。
We report single-crystal x-ray-diffraction measurements onwhich reveal a charge superstructure that appears below the density wave transitions previously observed in bulk data. From symmetry-constrained structure refinements we establish that the associated distortion mode can be described by two propagation vectorsandwith(Sb) or(As) and primarily involves in-plane displacements of the Ti atoms perpendicular to the Ti-O bonds. We also present angle-resolved photoemission spectroscopy measurements, which show band folding and backbending consistent with a density wave with the same wave-vectorsandassociated with Fermi-surface nesting, and muon-spin relaxation data, which show no indication of spin density wave order. The results provide direct evidence for phonon-assisted charge density wave order inand fully characterize a proximate ordered phase that could compete with superconductivity in doped.