Microscopic many-body theory of two-dimensional coherent spectroscopy of excitons and trions in atomically thin transition metal dichalcogenides

Abstract

We present a microscopic many-body theory of the recently measured two-dimensional coherent spectroscopy (2DCS) of excitons and trions in monolayer MoSe${}_2$ materials {[}K. Hao \textit{et al.}, Nano Lett. \textbf{16}, 5109 (2016){]}, where excitons and trions can be well interpreted as repulsive and attractive polarons, respectively, in the dilute limit of exciton density. We derive a simple relation for the 2DCS spectrum in terms of a modified, mixing time-dependent polaron Green function, which is valid in the single exciton limit. Our simulated spectra are in excellent qualitative agreement with experiments without introducing any phenomenological parameters such as decoherence rates. In particular, quantum beats between the off-diagonal crosspeaks in the experimental 2DCS spectra are well reproduced. Our work, therefore, clarifies the microscopic principle that underlies the observed optical signals of exciton-trion coherence. We find that there are two quantitative discrepancies between theory and experiment: the smaller than expected crosspeak strength and the slightly unsynchronized quantum beats at different crosspeaks. Tentatively, we attribute these residual discrepancies to the finite exciton density and the resultant polaron-polaron interaction, which is not taken into account in our theory.

10 pages, 5 figures

References in corpus (9)

• Two Dimensional Atomic Crystals
• Many-Body Theory of Trion Absorption Features in Two-Dimensional Semiconductors
• Time dependent impurity in ultracold fermions: orthogonality catastrophe and beyond
• Exciton-polaron interactions in monolayer WS${}_2$
• Heavy polarons in ultracold atomic Fermi superfluids at the BEC-BCS crossover: formalism and applications
• Exact quasiparticle properties of a heavy polaron in BCS Fermi superfluids
• Fermi polarons at finite temperature: Spectral function and rf-spectroscopy
• Multidimensional Spectroscopy of Time-Dependent Impurities in Ultracold Fermions
• Thermally stable p-wave repulsive Fermi polaron without a two-body bound state

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