Brightening and Control of Spin‐Forbidden Dark Excitons in a Strained Monolayer Semiconductor
Brightening and Control of Spin‐Forbidden Dark Excitons in a Strained Monolayer Semiconductor
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DOI：
10.1002/lpor.202300185
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发表时间：
2023-06
影响因子：
11
通讯作者：
Shuo Du;F. Jin;Xin-Bao Liu;Xin Huang;Yang Yang-Yang;Haifang Yang;Junjie Li;Qing-ming Zhang;Sheng Meng;Yang Guo;Changzhi Gu
中科院分区：
文献类型：
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作者：
Shuo Du;F. Jin;Xin-Bao Liu;Xin Huang;Yang Yang-Yang;Haifang Yang;Junjie Li;Qing-ming Zhang;Sheng Meng;Yang Guo;Changzhi Gu
暗激子由于其长寿命而在凝聚态物理、量子信息处理和光电子学中具有重要的应用价值。然而，由于违反自旋选择规则，直接光学访问暗激子仍然具有挑战性。在这里，提出了一种新的方案，通过创造人工的面外剪切应变，诱导有效的面内伪磁场，使WS2单层中的自旋禁戒暗激子变亮。为了揭示暗激子，对应变WS2单层进行低温磁光致发光实验。发现暗激子出现在亮激子之下59 meV处，并且表现出非对称的磁场依赖性，这与考虑了面外剪切应变对激子态自旋翻转过程的影响的模型一致。无场方案在暗激子应用于新型量子信息处理器件方面具有巨大的潜力。
Dark excitons are fascinating for condensed matter physics, quantum information processing, and optoelectronics due to their long lifetimes. However, direct optical access to dark excitons is still challenging due to the violation of the spin selection rule. Here, a new scheme for the brightening of spin‐forbidden dark exciton in WS2 monolayers by creating artificial out‐of‐plane shear strain that induces an effective in‐plane pseudo‐magnetic field is proposed. To reveal dark excitons, low‐temperature magneto‐photoluminescence experiments on the strained WS2 monolayers are performed. It is found that the dark excitons appear at 59 meV below the bright ones and exhibit an asymmetric magnetic field dependence, which is in agreement with the model taking into account the effect of the out‐of‐plane shear strain on spin‐flip processes of exciton states. The fieldless scheme has great potential in the application of dark excitons for new quantum information processing devices.