Mode-selective exciton-phonon dynamics in MoS2
| Autor: | Hu, Jianbo, Xiang, Yang, Ferrari, Beatrice Matilde, Vanacore, Giovanni Maria |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2021 |
| Předmět: |
Condensed Matter::Materials Science
Condensed Matter - Materials Science Quantum Physics Condensed Matter - Mesoscale and Nanoscale Physics Mesoscale and Nanoscale Physics (cond-mat.mes-hall) Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences Quantum Physics (quant-ph) Condensed Matter::Mesoscopic Systems and Quantum Hall Effect |
| Popis: | Two-dimensional crystals of transition metal dichalcogenides are emerging as promising candidates for next-generation optoelectronic and quantum devices. In such systems, the interaction between excitonic states and atomic vibrations is crucial for many fundamental properties, such as carrier mobilities, quantum coherence loss, and heat dissipation. In particular, to fully exploit their valley-selective excitations one has to understand the many-body exciton physics of zone-edge states. So far, theoretical and experimental studies have mainly focused on the exciton-phonon dynamics in high-energy direct excitons involving zone-center phonons. Here, we use ultrafast electron diffraction to investigate the structural dynamics occurring during nearly-resonant excitation of lowenergy indirect excitons in MoS2. By exploiting the large momentum carried by scattered electrons, we identify the selective excitation of in-plane K-phonon modes with 𝑬𝟐𝒈 𝟏 and 𝑬𝟏𝒖 symmetry. Our results highlight the strong selectivity of phononic excitations directly associated with the specific indirect-exciton nature of the wavelength-dependent electronic transitions triggered in the system. J.H. and G.M.V would like to remember the late Prof. Ahmed H. Zewail and are indebeted to him for his support and guidance in the initial phases of this project. J.H. acknowledges support from the Science Challenge Project (No. TZ2018001). |
| Databáze: | OpenAIRE |
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