Negative circular polarization emissions from WSe2/MoSe2 commensurate heterobilayers

Wei Ting Hsu, Li Syuan Lu, Po Hsun Wu, Ming Hao Lee, Peng Jen Chen, Pei Ying Wu, Yi-Chia Chou, Horng Tay Jeng, Lain Jong Li, Ming Wen Chu, Wen-Hao Chang*

*Corresponding author for this work

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Van der Waals heterobilayers of transition metal dichalcogenides with spin-valley coupling of carriers in different layers have emerged as a new platform for exploring spin/valleytronic applications. The interlayer coupling was predicted to exhibit subtle changes with the interlayer atomic registry. Manually stacked heterobilayers, however, are incommensurate with the inevitable interlayer twist and/or lattice mismatch, where the properties associated with atomic registry are difficult to access by optical means. Here, we unveil the distinct polarization properties of valley-specific interlayer excitons using epitaxially grown, commensurate WSe2/MoSe2 heterobilayers with well-defined (AA and AB) atomic registry. We observe circularly polarized photoluminescence from interlayer excitons, but with a helicity opposite to the optical excitation. The negative circular polarization arises from the quantum interference imposed by interlayer atomic registry, giving rise to distinct polarization selection rules for interlayer excitons. Using selective excitation schemes, we demonstrate the optical addressability for interlayer excitons with different valley configurations and polarization helicities.

Original languageEnglish
Article number1356
JournalNature Communications
Volume9
Issue number1
DOIs
StatePublished - 1 Dec 2018

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    Hsu, W. T., Lu, L. S., Wu, P. H., Lee, M. H., Chen, P. J., Wu, P. Y., Chou, Y-C., Jeng, H. T., Li, L. J., Chu, M. W., & Chang, W-H. (2018). Negative circular polarization emissions from WSe2/MoSe2 commensurate heterobilayers. Nature Communications, 9(1), [1356]. https://doi.org/10.1038/s41467-018-03869-7