Superior Valley Polarization and Coherence of 2s Excitons in Monolayer WSe2

Shao Yu Chen, Thomas Goldstein, Jiayue Tong, Takashi Taniguchi, Kenji Watanabe, Jun Yan

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15 Citations (Scopus)

Abstract

We report the experimental observation of 2s exciton radiative emission from monolayer tungsten diselenide, enabled by hexagonal boron nitride protected high-quality samples. The 2s luminescence is highly robust and persists up to 150 K, offering a new quantum entity for manipulating the valley degree of freedom. Remarkably, the 2s exciton displays superior valley polarization and coherence than 1s under similar experimental conditions. This observation provides evidence that the Coulomb-exchange-interaction-driven valley-depolarization process, the Maialle-Silva-Sham mechanism, plays an important role in valley excitons of monolayer transition metal dichalcogenides.

Original languageEnglish
Article number046402
Number of pages6
JournalPhysical Review Letters
Volume120
Issue number4
DOIs
Publication statusPublished - 25 Jan 2018
Externally publishedYes

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