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

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 b...

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Bibliographic Details
Published in:Nano letters 2017-02, Vol.17 (2), p.740-746
Main Authors: Wang, Zefang, Zhao, Liang, Mak, Kin Fai, Shan, Jie
Format: Article
Language:English
Subjects:
Chalcogens - chemistry
Chemistry
Disulfides - chemistry
Electrons
Materials Science
Molybdenum - chemistry
Nanotechnology
Physics
Science & Technology - Other Topics
Selenium Compounds - chemistry
Semiconductors
Spectrum Analysis - methods
Tungsten - chemistry
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Summary: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.
ISSN:1530-6984
1530-6992
DOI:10.1021/acs.nanolett.6b03855