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Coherent and incoherent coupling dynamics between neutral and charged excitons in Monolayer MoSe2



Kai Hao, Lixiang Xu, Philip Nagler, Akshay Singh, Kha Tran, Chandriker K. Dass, Rupert Huber, Tobias Korn, Xiaoqin Li, Galan Moody


The optical properties of semiconducting transition metal dichalcogenides are dominated by both neutral excitons (electron-hole pairs) and charged excitons (trions) that are stable even at room temperature. While trions directly influence charge transport properties, excitons may be relevant via exciton-trion coupling and conversion phenomena. In this work, we articulate the coherent and incoherent nature of exciton-trion coupling and the relevant timescales in monolayer MoSe2 using optical two-dimensional coherent spectroscopy. Coherent interaction between excitons and trions is definitively identified as quantum beating of cross-coupling peaks that persists for a few-hundred femtoseconds. At longer times up to 10 ps, the surprisingly large cross-coupling peaks are attributed to incoherent coupling between excitons and trions and suggests fast energy transfer even at cryogenic temperature likely due to phonon-assisted up-conversion and down-conversion processes.
Nano Letters


two-dimensional materials, exciton, coherent coupling, coherent spectroscopy


Hao, K. , Xu, L. , Nagler, P. , Singh, A. , Tran, K. , Dass, C. , Huber, R. , Korn, T. , Li, X. and Moody, G. (2016), Coherent and incoherent coupling dynamics between neutral and charged excitons in Monolayer MoSe2, Nano Letters, [online],, (Accessed April 22, 2024)
Created July 17, 2016, Updated October 12, 2021