Tailoring excitonic states of van der Waals bilayers through stacking configuration, band alignment, and valley spin

Wei Ting Hsu, Bo Han Lin, Li Syuan Lu, Ming Hao Lee, Ming Wen Chu, Lain Jong Li, Wang Yao, Wen Hao Chang*, Chih Kang Shih

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

55 Scopus citations

Abstract

Excitons in monolayer semiconductors have a large optical transition dipole for strong coupling with light. Interlayer excitons in heterobilayers feature a large electric dipole that enables strong coupling with an electric field and exciton-exciton interaction at the cost of a small optical dipole. We demonstrate the ability to create a new class of excitons in hetero- and homobilayers that combines advantages of monolayer and interlayer excitons, i.e., featuring both large optical and electric dipoles. These excitons consist of an electron confined in an individual layer, and a hole extended in both layers, where the carrier-species–dependent layer hybridization can be controlled through rotational, translational, band offset, and valley-spin degrees of freedom. We observe different species of layer-hybridized valley excitons, which can be used for realizing strongly interacting polaritonic gases and optical quantum controls of bidirectional interlayer carrier transfer.

Original languageEnglish
Article numbereaax7407
JournalScience Advances
Volume5
Issue number12
DOIs
StatePublished - 20 Dec 2019

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