Optical Coherence in Atomic-Monolayer Transition-Metal Dichalcogenides Limited by Electron-Phonon Interactions

P. Dey, J. Paul, Z. Wang, C. E. Stevens, C. Liu, A. H. Romero, J. Shan, D. J. Hilton, D. Karaiskaj

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Abstract

We systematically investigate the excitonic dephasing of three representative transition-metal dichalcogenides, namely, MoS2, MoSe2, and WSe2 atomic monolayer thick and bulk crystals, in order to gain a proper understanding of the factors that determine the optical coherence in these materials. Coherent nonlinear optical spectroscopy and temperature dependent absorption, combined with theoretical calculations of the phonon spectra, indicate electron-phonon interactions, to be the limiting factor. Surprisingly, the excitonic dephasing, differs only slightly between atomic monolayers and high quality bulk crystals, which indicates that material imperfections are not the limiting factor in atomically thin monolayer samples. The temperature dependence of the electronic band gap and the excitonic linewidth combined with "ab initio" calculations of the phonon energies and the phonon density of states reveal a strong interaction with the E' and E" phonon modes.

Original languageEnglish (US)
Article number127402
JournalPhysical Review Letters
Volume116
Issue number12
DOIs
StatePublished - Mar 25 2016

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All Science Journal Classification (ASJC) codes

  • Physics and Astronomy(all)

Cite this

Dey, P., Paul, J., Wang, Z., Stevens, C. E., Liu, C., Romero, A. H., Shan, J., Hilton, D. J., & Karaiskaj, D. (2016). Optical Coherence in Atomic-Monolayer Transition-Metal Dichalcogenides Limited by Electron-Phonon Interactions. Physical Review Letters, 116(12), [127402]. https://doi.org/10.1103/PhysRevLett.116.127402