Anisotropic Excitons Reveal Local Spin Chain Directions in a van der Waals Antiferromagnet
Anisotropic Excitons Reveal Local Spin Chain Directions in a van der Waals Antiferromagnet
复制标题
DOI：
10.1002/adma.202206585
复制
发表时间：
2023-02
影响因子：
29.4
通讯作者：
Dong Seob Kim;Di Huang;Chunhao Guo;Kejun Li;D. Rocca;Frank Y. Gao;Jeongheon Choe;David Lujan;Ting-Hsuan Wu;Kung‐Hsuan Lin;E. Baldini;Li Yang;Shivani Sharma;R. Kalaivanan;R. Sankar;Shang-Fan Lee;Y. Ping;Xiaoqin Li
中科院分区：
文献类型：
--
作者：
Dong Seob Kim;Di Huang;Chunhao Guo;Kejun Li;D. Rocca;Frank Y. Gao;Jeongheon Choe;David Lujan;Ting-Hsuan Wu;Kung‐Hsuan Lin;E. Baldini;Li Yang;Shivani Sharma;R. Kalaivanan;R. Sankar;Shang-Fan Lee;Y. Ping;Xiaoqin Li
材料科学领域长期以来的一个追求是寻找适用于集成信息存储、处理与传输的磁性半导体。范德华磁体为此提供了新的材料候选。最近，有报道称反铁磁体NiPS₃中尖锐的激子共振与磁序相关，即在奈尔温度以上，激子光致发光强度减弱。在此，研究发现最大激子发射的偏振发生局部旋转，揭示出三种可能的自旋链方向。这一发现对以往中子散射和光学实验中隐藏的反铁磁序有了新的认识。此外，研究提出缺陷束缚态是NiPS₃中一种有待探索的激子形成替代机制。支撑证据包括化学分析、激发功率、与厚度相关的光致发光以及第一性原理计算。这种激子形成机制也与强声子边带的存在相一致。本研究表明，各向异性激子光致发光可用于读出反铁磁体中的局部自旋链方向，并通过自旋 - 光子转换实现多功能器件。
A long‐standing pursuit in materials science is to identify suitable magnetic semiconductors for integrated information storage, processing, and transfer. Van der Waals magnets have brought forth new material candidates for this purpose. Recently, sharp exciton resonances in antiferromagnet NiPS3 have been reported to correlate with magnetic order, that is, the exciton photoluminescence intensity diminishes above the Néel temperature. Here, it is found that the polarization of maximal exciton emission rotates locally, revealing three possible spin chain directions. This discovery establishes a new understanding of the antiferromagnet order hidden in previous neutron scattering and optical experiments. Furthermore, defect‐bound states are suggested as an alternative exciton formation mechanism that has yet to be explored in NiPS3. The supporting evidence includes chemical analysis, excitation power, and thickness dependent photoluminescence and first‐principles calculations. This mechanism for exciton formation is also consistent with the presence of strong phonon side bands. This study shows that anisotropic exciton photoluminescence can be used to read out local spin chain directions in antiferromagnets and realize multi‐functional devices via spin‐photon transduction.