Measurement of the spin-forbidden dark excitons in MoS2 and MoSe2 monolayers

Measurement of the spin-forbidden dark excitons in MoS2 and MoSe2 monolayers

Článek WoS

Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field. Excitons control the optical properties of transition metal dichalcogenide monolayers. Here, the authors measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in hBN in magnetic fields up to 30T, and observe a brightening of the spin-forbidden dark excitons in MoS2.

Excitons with binding energies of a few hundreds of meV control the optical properties of transition metal dichalcogenide monolayers. Knowledge of the fine structure of these excitons is therefore essential to understand the optoelectronic properties of these 2D materials. Here we measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in boron nitride by magneto-photoluminescence spectroscopy in magnetic fields up to 30T. The experiments performed in transverse magnetic field reveal a brightening of the spin-forbidden dark excitons in MoS2 monolayer: we find that the dark excitons appear at 14meV below the bright ones. Measurements performed in tilted magnetic field provide a conceivable description of the neutral exciton fine structure. The experimental results are in agreement with a model taking into account the effect of the exchange interaction on both the bright and dark exciton states as well as the interaction with the magnetic field. Excitons control the optical properties of transition metal dichalcogenide monolayers. Here, the authors measure the exciton fine structure of MoS2 and MoSe2 monolayers encapsulated in hBN in magnetic fields up to 30T, and observe a brightening of the spin-forbidden dark excitons in MoS2.

QUANTUM BEATS; WSE2

QUANTUM BEATS; WSE2

Robert, C.; Han, B.; Kapuscinski, P.; Delhomme, A.; Faugeras, C.; Amand, T.; Molas, MR.; Bartos, M.; Watanabe, K.; Taniguchi, T. ; Urbaszek, B.; Potemski, M.; Marie, X.

2021

12.08.2020

NATURE PUBLISHING GROUP

LONDON

2041-1723

Nature Communications

11

1

Spojené království Velké Británie a Severního Irska

4037-1

4037-8

8

https://www.nature.com/articles/s41467-020-17608-4