Excitonic Valley Effects in Monolayer WS2 under High Magnetic Fields
详细信息 查看全文
- 作者：Gerd Plechinger ; Philipp Nagler ; Ashish Arora ; Andrés Granados del Águila ; Mariana V. Ballottin ; Tobias Frank ; Philipp Steinleitner ; Martin Gmitra ; Jaroslav Fabian ; Peter C. M. Christianen ; Rudolf Bratschitsch ; Christian Schüller ; Tobias Korn
- 刊名：Nano Letters
- 出版年：2016
- 出版时间：December 14, 2016
- 年：2016
- 卷：16
- 期：12
- 页码：7899-7904
- 全文大小：409K
- ISSN：1530-6992
文摘
Transition-metal dichalcogenides can be easily produced as atomically thin sheets, exhibiting the possibility to optically polarize and read out the valley pseudospin of extremely stable excitonic quasiparticles present in these 2D semiconductors. Here, we investigate a monolayer of tungsten disulfide in high magnetic fields up to 30 T via photoluminescence spectroscopy at low temperatures. The valley degeneracy is lifted for all optical features, particularly for excitons, singlet and triplet trions, for which we determine the g factor separately. While the observation of a diamagnetic shift of the exciton and trion resonances gives us insight into the real-space extension of these quasiparticles, magnetic field-induced valley polarization effects shed light onto the exciton and trion dispersion relations in reciprocal space. The field dependence of the trion valley polarizations is in line with the predicted trion splitting into singlet and triplet configurations.