Valley phonons and exciton complexes in a monolayer semiconductor
| Autor: | Xiaodong Xu, Dinh Van Tuan, Pasqual Rivera, Takashi Taniguchi, Jiaqiang Yan, David Mandrus, Minhao He, Min Yang, Hanan Dery, Wang Yao, Nathan P. Wilson, Kenji Watanabe, Hongyi Yu |
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| Jazyk: | angličtina |
| Rok vydání: | 2020 |
| Předmět: |
Photoluminescence
Phonon Exciton Science FOS: Physical sciences General Physics and Astronomy 02 engineering and technology Two-dimensional materials 01 natural sciences Article General Biochemistry Genetics and Molecular Biology Condensed Matter::Materials Science Lattice (order) Condensed Matter::Superconductivity Mesoscale and Nanoscale Physics (cond-mat.mes-hall) 0103 physical sciences Monolayer lcsh:Science 010306 general physics Physics Condensed Matter - Materials Science Multidisciplinary Condensed Matter - Mesoscale and Nanoscale Physics Condensed matter physics Scattering business.industry Condensed Matter::Other Materials Science (cond-mat.mtrl-sci) General Chemistry 021001 nanoscience & nanotechnology Condensed Matter::Mesoscopic Systems and Quantum Hall Effect Brillouin zone Semiconductor lcsh:Q Condensed Matter::Strongly Correlated Electrons 0210 nano-technology business |
| Zdroj: | Nature Communications, Vol 11, Iss 1, Pp 1-7 (2020) Nature Communications |
| ISSN: | 2041-1723 |
| Popis: | The coupling between spin, charge, and lattice degrees of freedom plays an important role in a wide range of fundamental phenomena. Monolayer semiconducting transitional metal dichalcogenides have emerged as an outstanding platform for studying these coupling effects because they possess unique spin-valley locking physics for hosting rich excitonic species and the reduced screening for strong Coulomb interactions. Here, we report the observation of multiple valley phonons, phonons with momentum vectors pointing to the corners of the hexagonal Brillouin zone, and the resulting exciton complexes in the monolayer semiconductor WSe2. From Lande g-factor and polarization analyses of photoluminescence peaks, we find that these valley phonons lead to efficient intervalley scattering of quasi particles in both exciton formation and relaxation. This leads to a series of photoluminescence peaks as valley phonon replicas of dark trions. Using identified valley phonons, we also uncovered an intervalley exciton near charge neutrality, and extract its short-range electron-hole exchange interaction to be about 10 meV. Our work not only identifies a number of previously unknown 2D excitonic species, but also shows that monolayer WSe2 is a prime candidate for studying interactions between spin, pseudospin, and zone-edge phonons. to appear in Nature Communications |
| Databáze: | OpenAIRE |
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