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Twist-tailoring Coulomb correlations in van der Waals homobilayers
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Anna Girnghuber,
Kai-Qiang Lin ,
Leonard Weigl,
Marlene Liebich,
Chaw-Keong Yong,
Roland Gillen ,
Janina Maultzsch ,
John M. Lupton,
Ermin Malic ,
Rupert Huber
Nature Communications, Volume: 11, Issue: 1
Swansea University Author:
Roland Gillen
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DOI (Published version): 10.1038/s41467-020-16069-z
Abstract
The recent discovery of artificial phase transitions induced by stacking monolayer materials at magic twist angles represents a paradigm shift for solid state physics. Twist-induced changes of the single-particle band structure have been studied extensively, yet a precise understanding of the underl...
| Published in: | Nature Communications |
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| ISSN: | 2041-1723 |
| Published: |
Springer Science and Business Media LLC
2020
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| Online Access: |
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| URI: | https://cronfa.swan.ac.uk/Record/cronfa66661 |
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| Abstract: |
The recent discovery of artificial phase transitions induced by stacking monolayer materials at magic twist angles represents a paradigm shift for solid state physics. Twist-induced changes of the single-particle band structure have been studied extensively, yet a precise understanding of the underlying Coulomb correlations has remained challenging. Here we reveal in experiment and theory, how the twist angle alone affects the Coulomb-induced internal structure and mutual interactions of excitons. In homobilayers of WSe2, we trace the internal 1s–2p resonance of excitons with phase-locked mid-infrared pulses as a function of the twist angle. Remarkably, the exciton binding energy is renormalized by up to a factor of two, their lifetime exhibits an enhancement by more than an order of magnitude, and the exciton-exciton interaction is widely tunable. Our work opens the possibility of tailoring quasiparticles in search of unexplored phases of matter in a broad range of van der Waals heterostructures. |
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| College: |
Faculty of Science and Engineering |
| Funders: |
We thank Martin Furthmeier for technical assistance and Jens Kunstmann for fruitful discussions. This work was supported by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation)—Project-ID, 314695032—SFB 1277 (Subprojects A05 and B03). The Chalmers group acknowledges funding from the European Union’s Horizon 2020 research and innovation program under grant agreement No. 881603 (Graphene Flagship) as well as from the Swedish Research Council (VR, project number 2018-00734). |
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1 |