Luminescent Emission of Excited Rydberg Excitons from Monolayer WSe 2

• Published in: Nano letters Vol. 19; no. 4; pp. 2464 - 2471
• Main Authors: Chen, Shao-Yu, Lu, Zhengguang, Goldstein, Thomas, Tong, Jiayue, Chaves, Andrey, Kunstmann, Jens, Cavalcante, L S R, Woźniak, Tomasz, Seifert, Gotthard, Reichman, D R, Taniguchi, Takashi, Watanabe, Kenji, Smirnov, Dmitry, Yan, Jun
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 10.04.2019
• Subjects: Chemistry; Materials Science; Physics; Science & Technology - Other Topics; Zeeman shift; magnetic dipole moment; Rydberg exciton; diamagnetic shift; tungsten diselenide
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/acs.nanolett.9b00029

We report the experimental observation of radiative recombination from Rydberg excitons in a two-dimensional semiconductor, monolayer WSe , encapsulated in hexagonal boron nitride. Excitonic emission up to the 4 s excited state is directly observed in photoluminescence spectroscopy in an out-of-plane magnetic field up to 31 T. We confirm the progressively larger exciton size for higher energy excited states through diamagnetic shift measurements. This also enables us to estimate the 1 s exciton binding energy to be about 170 meV, which is significantly smaller than most previous reports. The Zeeman shift of the 1 s to 3 s states, from both luminescence and absorption measurements, exhibits a monotonic increase of the g-factor, reflecting nontrivial magnetic-dipole-moment differences between ground and excited exciton states. This systematic evolution of magnetic dipole moments is theoretically explained from the spreading of the Rydberg states in momentum space.