In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in La_2−xSr_xCuO₄ and La_1.8−xEu_0.2Sr_xCuO₄. Ultra high energy resolution experiments demonstrate the importance of the separation of inelastic and elastic scattering processes. Long-range temperature-dependent stripe order is only found below optimal doping. At higher doping, short-range temperature-independent correlations are present up to the highest doping measured. This transformation is distinct from and preempts the pseudogap critical doping. We argue that the doping and temperature-independent short-range correlations originate from unresolved electron–phonon coupling that broadly peaks at the stripe ordering vector. In La_2−xSr_xCuO₄, long-range static stripe order vanishes around optimal doping and we discuss both quantum critical and crossover scenarios.

在高温铜酸盐超导体中，条带序广泛地指分别具有八个和四个晶格单元的耦合自旋和电荷调制。这种条纹顺序如何在最佳掺杂中演变仍然是一个有争议的问题。在这里，我们提出了 La _{2− x} Sr _x CuO ₄和 La _{1.8− x} Eu _0.2 Sr _x CuO ₄中弱电荷相关性的系统共振非弹性 X 射线散射研究。超高能量分辨率实验证明了分离非弹性和弹性散射过程的重要性。仅在低于最佳掺杂的情况下才发现长程温度依赖性条带顺序。在较高掺杂度下，直到测量到的最高掺杂度为止，都存在与温度无关的短程相关性。这种转变不同于赝能隙临界掺杂，并且取代了赝能隙临界掺杂。我们认为，掺杂和与温度无关的短程相关性源于未解决的电子声子耦合，该耦合在条带排序向量处广泛达到峰值。在 La _{2− x} Sr _x CuO ₄中，长程静态条带序在最佳掺杂附近消失，我们讨论了量子临界和交叉场景。