Negative valley polarization in doped monolayer MoSe 2
Negative valley polarization in doped monolayer MoSe 2
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掺杂单层 MoSe 2 中的负谷极化
DOI：
10.1039/d1cp03490a
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发表时间：
2021
影响因子：
3.3
通讯作者：
Yan, Jun
中科院分区：
文献类型：
--
作者：
Wu, Yueh-Chun;Taniguchi, Takashi;Watanabe, Kenji;Yan, Jun
单层二硒化钼 (1L-MoSe2) 在过渡金属二硫族化物材料家族中脱颖而出，因为谷偏振的光学生成效率低下。在这里，我们表明，使用电荷掺杂与外部磁场相结合，可以有效地控制 1L-MoSe2 的谷极化。最值得注意的是，谷偏振可以调整为负值，其中较高能量的塞曼模式发射比较低能量的塞曼模式发射更强烈。我们的实验观察结果是用谷选择性激子电荷修整来解释的，当栅极诱导掺杂在存在塞曼分裂的情况下主要填充一个谷时就会显现出来。
Monolayer molybdenum di-selenide (1L-MoSe2) stands out in the transition metal dichalcogenide family of materials as an outlier where optical generation of valley polarization is inefficient. Here we show that using charge doping in conjunction with an external magnetic field, the valley polarization of 1L-MoSe2 can be controlled effectively. Most remarkably, the valley polarization can be tuned to negative values, where the higher energy Zeeman mode emission is more intense than the lower energy one. Our experimental observations are interpreted with valley-selective exciton-charge dressing that manifests when gate induced doping populates predominantly one valley in the presence of Zeeman splitting.