AI 中文总结
本研究结合理论计算与光学实验，揭示了CrPS$_4$的电子和激子性质，明确了其磁相变的光学标识，为反铁磁体的激子研究及磁有序调控提供了新方向。
AI 中文摘要
层状范德华磁性半导体为研究与自旋、晶格自由度耦合的激子现象提供了多功能平台，可使激子作为探测磁有序的灵敏探针。CrPS$_4$是一种层状反铁磁半导体，具有丰富的激子特征，其微观起源及与磁有序的关联尚未完全明晰。本研究结合多体微扰理论、动力学平均场理论和光致发光实验，探究体相CrPS$_4$的电子与激子性质。计算表明，反铁磁相下CrPS$_4$为直接带隙半导体，带隙为2.48 eV；理论预测多个亚带隙激子跃迁，包括多个自旋允许激子及一个额外的自旋翻转激发，后者主要局域在Cr$^{3+}$离子上。温度和磁场依赖的光学测量揭示了热驱动下激子在局域态间的重分布，并识别出特征能量位移，其为CrPS$_4$磁相变提供了清晰的光学标识。这些结果为反铁磁体的激子跃迁提供了新见解，并为全光学传感及光驱动调控其磁有序指明了潜在途径。
英文摘要
Layered van der Waals magnetic semiconductors provide a versatile platform for exploring excitonic phenomena intertwined with spin and lattice degrees of freedom, enabling excitons to act as sensitive probes of magnetic order. CrPS$_4$ is a layered antiferromagnetic semiconductor that hosts rich excitonic features whose microscopic origin and connection to magnetic ordering remain incompletely understood. Here, we investigate the electronic and excitonic properties of bulk CrPS$_4$ using a combination of many-body perturbation theory, dynamical mean-field theory, and photoluminescence-based experiments. Our calculations establish CrPS$_4$ as a direct-gap semiconductor with a bandgap of 2.48~eV in the antiferromagnetic phase. Several sub-bandgap excitonic transitions are predicted by theory, comprising multiple spin-allowed excitons and an additional spin-flip excitation, predominantly localized on the Cr$^{3+}$ ions. Temperature- and magnetic-field-dependent optical measurements reveal thermally driven exciton redistribution among localized states and identify characteristic energy shifts that provide clear optical signatures of magnetic phase transitions in CrPS$_4$. These results provide new insights into the excitonic transitions of antiferromagnets and suggest potential routes for all-optical sensing and light-driven control of their magnetic order.
Comments12 pages, 5 figures
