Exciton lifetime and optical linewidth profile via exciton-phonon interactions: Theory and first-principles calculations for monolayer MoS${}_2$

Abstract

Exciton dynamics dictate the evolution of photoexcited carriers in photovoltaic and optoelectronic devices. However, interpreting their experimental signatures is a challenging theoretical problem due to the presence of both electron-phonon and many-electron interactions. We develop and apply here a first-principles approach to exciton dynamics resulting from exciton-phonon coupling in monolayer MoS2 and reveal the highly selective nature of exciton-phonon coupling due to the internal spin structure of excitons, which leads to a surprisingly long lifetime of the lowest energy bright A exciton. Moreover, we show that optical absorption processes rigorously require a second-order perturbation theory approach, with photon and phonon treated on an equal footing, as proposed by Toyozawa and Hopfield. Such a treatment, thus far neglected in first-principles studies, gives rise to off-diagonal exciton-phonon coupling matrix elements, which are critical for the description of dephasing mechanisms, and yields exciton linewidths in excellent agreement with experiment.

11 pages, 4 figures

References in corpus (8)

• {\it Ab--initio} finite temperature excitons
• Phonon Sidebands in Transition Metal Dichalcogenides
• Electron-Phonon Coupling from $\text{Ab Initio}$ Linear-Response Theory within the $GW$ Method: Correlation-Enhanced Interactions and Superconductivity in Ba${}_{1-x}$K${}_x$BiO${}_3$
• Intrinsic Lifetime of Higher Excitonic States in Tungsten Diselenide Monolayers
• Exciton-phonon coupling strength in single-layer MoSe2 at room temperature
• Signatures of Dimensionality and Symmetry in Exciton Bandstructure: Consequences for Time-Evolution
• Imaging dynamic exciton interactions and coupling in transition metal dichalcogenides
• Ab initio calculations of spin-nonconserving exciton-phonon scattering in monolayer transition metal dichalcogenides

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• Phonon-mediated exciton relaxation in two-dimensional semiconductors: selection rules and relaxation pathways
• Mixed quantum-classical modeling of exciton-phonon scattering in solids: Application to optical linewidths of monolayer MoS2
• Origin of interlayer exciton-phonon coupling in 2D heterostructures
• Wannier-Function-Based Approach to Coupled Exciton-Phonon-Photon Dynamics in Two-Dimensional Semiconductors
• Designable exciton mixing through layer alignment in WS${}_2$-graphene heterostructures
• First-Principles Insights into Excitonic and Electron-Phonon Effects in van der Waals Heterostructures
• Flipping of electronic spins in BiFeO${}_3$ via chiral $d-d$ excitations
• Solvers for the Hermitian and the pseudo-Hermitian Bethe-Salpeter equation in the Yambo code: Implementation and Performance
• Symmetries in zero and finite center-of-mass momenta excitons