Probing the Spin-Polarized Electronic Band Structure in Monolayer Transition Metal Dichalcogenides by Optical Spectroscopy

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• 作者：Zefang Wang ; Liang Zhao ; Kin Fai MakJie Shan
• 刊名：Nano Letters
• 出版年：2017
• 出版时间：February 8, 2017
• 年：2017
• 卷：17
• 期：2
• 页码：740-746
• 全文大小：455K
• ISSN：1530-6992

文摘

We study the electronic band structure in the K/K′ valleys of the Brillouin zone of monolayer WSe₂ and MoSe₂ by optical reflection and photoluminescence spectroscopy on dual-gated field-effect devices. Our experiment reveals the distinct spin polarization in the conduction bands of these compounds by a systematic study of the doping dependence of the A and B excitonic resonances. Electrons in the highest-energy valence band and the lowest-energy conduction band have antiparallel spins in monolayer WSe₂ and parallel spins in monolayer MoSe₂. The spin splitting is determined to be hundreds of meV for the valence bands and tens of meV for the conduction bands, which are in good agreement with first-principles calculations. These values also suggest that both n- and p-type WSe₂ and MoSe₂ can be relevant for spin- and valley-based applications.