AI 中文总结
本文以静水压力为调控参数，探究NiPS₃磁激子的亮态-暗态转变机制，发现其光学亮度由高阶关联机制主导，为关联量子磁体中纠缠磁激子研究提供框架。
AI 中文摘要
最近在范德华（vdW）反铁磁体NiPS₃中发现的磁激子例证了相关现象，展现出多种独特特性。尽管已开展大量研究，其诸多物理机制仍未明确，关键问题包括：尽管名义上属于自旋禁阻跃迁，NiPS₃磁激子为何如此尖锐且光学明亮，这对该激子的正确理解与实际调控构成重大挑战。一个亟待解决的问题是，这种特性在多大程度上源于化学无序、磁性弱化、晶格修饰或亮激子自身的本征不稳定性，相关答案将对理论模型施加严格约束。本文采用静水压力作为清洁、连续、可逆且可原位调控的参数来解决这些问题。研究发现，仅0.4 GPa的压力就会显著抑制尖锐的光致发光峰，1.5 GPa时该峰完全淬灭，且过程具有可逆性。关键的是，尽管奈尔温度升高，但从拉曼、X射线吸收、核磁共振谱及第一性原理多体计算结果可知，这种亮态到暗态的转变并未伴随磁性、晶体学或电子结构的重构。研究结果表明，磁激子的光学亮度与化学无序、晶格膨胀及磁有序弱化无关，说明高阶关联机制主导亮激子。本文进一步提出受实验约束的微观场景，涉及激子配对、晶体场调控的自旋轨道混合及对称性破缺，为未来在关联量子磁体中研究纠缠磁激子提供框架。
英文摘要
The recently discovered magnetic exciton in the van der Waals (vdW) antiferromagnet NiPS3 exemplifies these phenomena, exhibiting several distinctive characteristics. Despite extensive investigation, much of its physics remains unresolved, with key questions about why the NiPS3 magnetic exciton is so sharp and optically bright despite the nominally spin-forbidden transition, posing significant challenges to a proper understanding and practical manipulation of the exciton. An urgent question is to what extent it is due to chemical disorder, magnetic weakening, lattice modification, or intrinsic instability of the bright exciton itself: answers to which will put stringent constraints on possible theoretical models. Here we address these questions using hydrostatic pressure as a clean, continuous, reversible, and in-situ tuning parameter. We find that the sharp photoluminescence peak is drastically suppressed by as little as 0.4 GPa and completely quenched by 1.5 GPa, with demonstrating its reversibility. Crucially, this bright-to-dark conversion occurs without magnetic, crystallographic, or electronic reconstruction despite an increase in the Neel temperature, as established by Raman, X-ray absorption, nuclear magnetic resonance spectroscopy, and first-principles many-body calculations. Our results demonstrate that the optical brightness of the magnetic exciton is independent of chemical disorder, lattice expansion, and weakening of magnetic order, indicating that a higher-order correlated mechanism governs the bright exciton. We further propose experimentally constrained microscopic scenarios involving exciton pairing, crystal-field-controlled spin-orbit mixing, and symmetry breaking, providing a framework for future tests of entangled magnetic exciton in correlated quantum magnets.
CommentsOur findings indicate that the sharp coherence of the entangled magnetic exciton benefits from its delicate quantum nature, and its optical brightness can be activated by exciton pairing or spin-orbit coupling, while its fragility under external control is achievable through a high-order perturbation rather than a first-order transition
