Exciton-exciton interactions in van der Waals heterobilayers
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arXiv
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| Autores principales: | , , , , , , , , , |
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| Formato: | Preprint |
| Publicado: |
2023
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| Materias: | |
| Acceso en línea: | |
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| _version_ | 1866913479498137600 |
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| author | Steinhoff, Alexander Wietek, Edith Florian, Matthias Schulz, Tommy Taniguchi, Takashi Watanabe, Kenji Zhao, Shen Högele, Alexander Jahnke, Frank Chernikov, Alexey |
| author_facet | Steinhoff, Alexander Wietek, Edith Florian, Matthias Schulz, Tommy Taniguchi, Takashi Watanabe, Kenji Zhao, Shen Högele, Alexander Jahnke, Frank Chernikov, Alexey |
| contents | Exciton-exciton interactions are key to understanding non-linear optical and transport phenomena in van der Waals heterobilayers, which emerged as versatile platforms to study correlated electronic states. We present a combined theory-experiment study of excitonic many-body effects based on first-principle band structures and Coulomb interaction matrix elements. Key to our approach is the explicit treatment of the fermionic substructure of excitons and dynamical screening effects for density-induced energy renormalization and dissipation. We demonstrate that dipolar blue shifts are almost perfectly compensated by many-body effects, mainly by screening-induced self-energy corrections. Moreover, we identify a crossover between attractive and repulsive behavior at elevated exciton densities. Theoretical findings are supported by experimental studies of spectrally-narrow interlayer excitons in atomically-reconstructed, hBN-encapsulated MoSe$_2$/WSe$_2$ heterobilayers. Both theory and experiment show energy renormalization on a scale of a few meV even for high injection densities in the vicinity of the Mott transition. Our results revise the established picture of dipolar repulsion dominating exciton-exciton interactions in van der Waals heterostructures and open up opportunities for their external design. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2310_18328 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Exciton-exciton interactions in van der Waals heterobilayers Steinhoff, Alexander Wietek, Edith Florian, Matthias Schulz, Tommy Taniguchi, Takashi Watanabe, Kenji Zhao, Shen Högele, Alexander Jahnke, Frank Chernikov, Alexey Mesoscale and Nanoscale Physics Quantum Gases Exciton-exciton interactions are key to understanding non-linear optical and transport phenomena in van der Waals heterobilayers, which emerged as versatile platforms to study correlated electronic states. We present a combined theory-experiment study of excitonic many-body effects based on first-principle band structures and Coulomb interaction matrix elements. Key to our approach is the explicit treatment of the fermionic substructure of excitons and dynamical screening effects for density-induced energy renormalization and dissipation. We demonstrate that dipolar blue shifts are almost perfectly compensated by many-body effects, mainly by screening-induced self-energy corrections. Moreover, we identify a crossover between attractive and repulsive behavior at elevated exciton densities. Theoretical findings are supported by experimental studies of spectrally-narrow interlayer excitons in atomically-reconstructed, hBN-encapsulated MoSe$_2$/WSe$_2$ heterobilayers. Both theory and experiment show energy renormalization on a scale of a few meV even for high injection densities in the vicinity of the Mott transition. Our results revise the established picture of dipolar repulsion dominating exciton-exciton interactions in van der Waals heterostructures and open up opportunities for their external design. |
| title | Exciton-exciton interactions in van der Waals heterobilayers |
| topic | Mesoscale and Nanoscale Physics Quantum Gases |
| url | https://arxiv.org/abs/2310.18328 |