Excited-State Trions in Monolayer WS2

We discover an excited bound three-particle state, the 2s trion, appearing energetically below the 2s exciton in monolayer WS2, using absorption spectroscopy and ab initio GW and Bethe-Salpeter equation calculations. The measured binding energy of the 2s trion (22 meV) is smaller compared to the 1s...

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Bibliographic Details
Published in:Physical review letters 2019-10, Vol.123 (16), p.1
Main Authors: Arora, Ashish, Deilmann, Thorsten, Reichenauer, Till, Kern, Johannes, de Vasconcellos, Steffen Michaelis, Rohlfing, Michael, Bratschitsch, Rudolf
Format: Article
Language:English
Subjects:
Bethe-Salpeter equation
Energy measurement
Excitation spectra
Excitons
Monolayers
Oscillator strengths
Trions
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Summary:We discover an excited bound three-particle state, the 2s trion, appearing energetically below the 2s exciton in monolayer WS2, using absorption spectroscopy and ab initio GW and Bethe-Salpeter equation calculations. The measured binding energy of the 2s trion (22 meV) is smaller compared to the 1s intravalley and intervalley trions (37 and 31 meV). With increasing temperature, the 1s and 2s trions transfer their oscillator strengths to the respective neutral excitons, establishing an optical fingerprint of trion-exciton resonance pairs. Our discovery underlines the importance of trions for the entire excitation spectrum of two-dimensional semiconductors.
ISSN:0031-9007
1079-7114
DOI:10.1103/PhysRevLett.123.167401