Large photoluminescence enhancement by an out-of-plane magnetic field in exfoliated WS$_2$ flakes
| Autor: | Sun, Sibai, Dang, Jianchen, Xie, Xin, Yu, Yang, Yang, Longlong, Xiao, Shan, Wu, Shiyao, Peng, Kai, Song, Feilong, Wang, Yunuan, Yang, Jingnan, Qian, Chenjiang, Zuo, Zhanchun, Xu, Xiulai |
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| Rok vydání: | 2020 |
| Předmět: | |
| Zdroj: | Chin. Phys. Lett. 37, 087801 (2020) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1088/0256-307X/37/8/087801 |
| Popis: | We report an out-of-plane magnetic field induced large photoluminescence enhancement in WS${}_2$ flakes at $4$ K, in contrast to the photoluminescence enhancement provided by in-plane field in general. Two mechanisms for the enhancement are proposed. One is a larger overlap of electron and hole caused by the magnetic field induced confinement. The other is that the energy difference between $\Lambda$ and K valleys is reduced by magnetic field, and thus enhancing the corresponding indirect-transition trions. Meanwhile, the Land\'e g factor of the trion is measured as $-0.8$, whose absolute value is much smaller than normal exciton, which is around $|-4|$. A model for the trion g factor is presented, confirming that the smaller absolute value of Land\'e g factor is a behavior of this $\Lambda$-K trion. By extending the valley space, we believe this work provides a further understanding of the valleytronics in monolayer transition metal dichalcogenides. Comment: 15 pages, 4 figures |
| Databáze: | arXiv |
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