The nature of the spin excitations in superconducting cuprates is a key question toward a unified understanding of the cuprate physics from long-range antiferromagnetism to superconductivity. The intense spin excitations up to the over-doped regime revealed by resonant inelastic X-ray scattering bring new insights as well as questions like how to understand their persistence or their relation to the collective excitations in ordered magnets (magnons). Here, we study the evolution of the spin excitations upon hole-doping the superconducting cuprate Bi₂Sr₂CaCu₂O_8+δ by disentangling the spin from the charge excitations in the experimental cross section. We compare our experimental results against density matrix renormalization group calculations for a t-J-like model on a square lattice. Our results unambiguously confirm the persistence of the spin excitations, which are closely connected to the persistence of short-range magnetic correlations up to high doping. This suggests that the spin excitations in hole-doped cuprates are related to magnons—albeit short-ranged.

超导铜酸盐中自旋激发的性质是统一理解从长程反铁磁性到超导的铜酸盐物理学的关键问题。共振非弹性 X 射线散射所揭示的直到过度掺杂状态的强烈自旋激发带来了新的见解以及诸如如何理解它们的持久性或它们与有序磁体（磁振子）中的集体激发的关系等问题。在这里，我们研究了空穴掺杂超导铜酸盐 Bi ₂ Sr ₂ CaCu ₂ O _{8+ δ时自旋激发的演变}通过从实验横截面中的电荷激发中解开自旋。我们将我们的实验结果与方格上t - J类模型的密度矩阵重整化群计算进行比较。我们的结果明确地证实了自旋激发的持久性，这与高掺杂的短程磁相关的持久性密切相关。这表明空穴掺杂铜酸盐中的自旋激发与磁振子有关——尽管是短程的。