Theory of coherent phonons coupled to excitons
arXiv:2406.15221 · doi:10.1038/s41699-024-00474-9
Abstract
The interaction of excitons with lattice vibrations underlies the scattering from bright to dark excitons as well as the coherent modulation of the exciton energy. Unlike the former mechanism, which involves phonons with finite momentum, the latter can be exclusively attributed to {\it coherent phonons} with zero momentum. We here lay down the microscopic theory of coherent phonons interacting with resonantly pumped bright excitons and provide the explicit expression of the corresponding coupling. The coupling notably resembles the exciton-phonon one, but with a crucial distinction: it contains the bare electron-phonon matrix elements rather than the screened ones. Our theory predicts that the exciton energy features a polaronic-like red-shift and monochromatic oscillations or beatings, depending on the number of coupled optical modes. Both the red-shift and the amplitude of the oscillations are proportional to the excitation density and to the square of the exciton-coherent-phonon coupling. We validate our analytical findings through comparisons with numerical simulations of time-resolved optical absorbance in resonantly pumped MoS monolayers.
References in corpus (18)
- Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
- Tightly bound excitons in monolayer WSe2
- Exciton band structure of monolayer MoS2
- Excitons versus electron-hole plasma in monolayer transition metal dichalcogenide semiconductors
- {\it Ab--initio} finite temperature excitons
- Phonon Sidebands in Transition Metal Dichalcogenides
- Optical properties of correlated materials -- Generalized Peierls approach and its application to VO2
- Optically discriminating carrier-induced quasiparticle band gap and exciton energy renormalization in monolayer MoS2
- Nonclassical Exciton Diffusion in Monolayer WSe2
- Real-time GW: Toward an ab initio description of the ultrafast carrier and exciton dynamics in two-dimensional materials
- Exciton-phonon coupling strength in single-layer MoSe2 at room temperature
- Exciton lifetime and optical linewidth profile via exciton-phonon interactions: Theory and first-principles calculations for monolayer MoS
- Some Exact Properties of the Nonequilibrium Response Function for Transient Photoabsorption
- Time-linear scaling NEGF methods for real-time simulations of interacting electrons and bosons. I. Formalism
- Strong Coupling of Coherent Phonons to Excitons in Semiconducting Monolayer MoTe
- Exciton-phonon interaction calls for a revision of the "exciton" concept
- Photoinduced coherent modulation of an excitonic resonance via coupling with coherent optical phonons
- From carriers and virtual excitons to exciton populations: Insights into time-resolved ARPES spectra from an exactly solvable model
Cited by in corpus (4)
- Coherent Modulation of Two-Dimensional Moiré States with On-Chip THz Waves
- Excitonic Bloch equations from first principles
- Advancing Simulations of Coupled Electron and Phonon Nonequilibrium Dynamics Using Adaptive and Multirate Time Integration
- Wannier-Function-Based Approach to Coupled Exciton-Phonon-Photon Dynamics in Two-Dimensional Semiconductors