Observation of Intervalley Biexcitonic Optical Stark Effect in Monolayer WS[subscript 2]
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Gedik_Observation of intervalley.pdf
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Author(s)
Lui, Chun Hung
Lee, Yi-Hsien
Sie, Edbert Jarvis
Gedik, Nuh
Kong, Jing
Date Issued
November 2016
Journal
Nano Letters
Publisher
American Chemical Society (ACS)
Citation
Sie, Edbert J., et al. “Observation of Intervalley Biexcitonic Optical Stark Effect in Monolayer WS[subscript 2].” Nano Letters, vol. 16, no. 12, Dec. 2016, pp. 7421–26.
Version
Author's final manuscript
Abstract
Coherent optical driving can effectively modify the properties of electronic valleys in transition metal dichalcogenides. Here, we observe a new type of optical Stark effect in monolayer WS[subscript 2], one that is mediated by intervalley biexcitons under the blue-detuned driving with circularly polarized light. We find that such helical optical driving not only induces an exciton energy downshift at the excitation valley but also causes an anomalous energy upshift at the opposite valley, which is normally forbidden by the exciton selection rules but now made accessible through the intervalley biexcitons. These findings reveal the critical, but hitherto neglected, role of biexcitons to couple the two seemingly independent valleys, and to enhance the optical control in valleytronics. Keywords: WS[subscript 2], valley, biexciton, blue detuned, optical Stark effect, ultrafast optics
MIT Department
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Physics
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Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
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DOI of Published Version
https://doi.org/10.1021/ACS.NANOLETT.6B02998
