| 1. |
- Sandner, Fabian, et al.
(author)
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Femtosecond nanoscopy of charge carrier dynamics in van der Waals heterostructures
- 2022
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In: Optics InfoBase Conference Papers.
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Conference paper (peer-reviewed)abstract
- Ultrafast polarization nanoscopy traces the femtosecond interlayer tunneling and the density-dependent Mott transition of strongly bound excitons in custom-tailored van der Waals heterostructures with subcycle temporal and nanometer spatial resolution.
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| 2. |
- Siday, Thomas, et al.
(author)
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Ultrafast Nanoscopy of an Exciton Mott Transition in Twisted Bilayer WSe 2
- 2022
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In: International Conference on Infrared, Millimeter, and Terahertz Waves, IRMMW-THz. - 2162-2027 .- 2162-2035. ; August
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Conference paper (peer-reviewed)abstract
- The density-driven transition of an exciton gas into a plasma of unbound electron-hole pairs has provided a compelling testbed for exploring many-body physics. Here, we use ultrafast polarization nanoscopy to trace a Mott transition of excitons in a twisted bilayer of WSe2. An initially monomolecular recombination of optically dark excitons continuously evolves into bimolecular recombination of unbound electrons and holes as the density is increased. Furthermore, we reveal directly how the Mott transition varies on nanometer length scales, demonstrating how the technique is indispensable in the study of intrinsically disordered van der Waals materials.
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| 3. |
- Zizlsperger, Martin, et al.
(author)
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Ultrafast nanoscopy of an excitonic insulator-metal transition in twisted bilayer WSe 2
- 2022
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In: CLEO: QELS_Fundamental Science in Proceedings Conference on Lasers and Electro-Optics. - 9781557528209 - 9781957171050
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Conference paper (peer-reviewed)abstract
- Many-body interactions between excitons in a transition-metal dichalcogenide bilayer drive a transition into an electron-hole liquid at high densities. Using ultrafast polarization nanoscopy, we unveil spatiotemporal dynamics of this continuous Mott transition on the nanoscale.
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| 4. |
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- 2019
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Journal article (peer-reviewed)
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| 5. |
- Gericke, Martin, et al.
(author)
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The European Polysaccharide Network of Excellence (EPNOE) research roadmap 2040: Advanced strategies for exploiting the vast potential of polysaccharides as renewable bioresources
- 2024
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In: Carbohydrate Polymers. - : Elsevier BV. - 0144-8617 .- 1879-1344. ; 326
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Journal article (peer-reviewed)abstract
- Polysaccharides are among the most abundant bioresources on earth and consequently need to play a pivotal role when addressing existential scientific challenges like climate change and the shift from fossil-based to sustainable biobased materials. The Research Roadmap 2040 of the European Polysaccharide Network of Excellence (EPNOE) provides an expert's view on how future research and development strategies need to evolve to fully exploit the vast potential of polysaccharides as renewable bioresources. It is addressed to academic researchers, companies, as well as policymakers and covers five strategic areas that are of great importance in the context of polysaccharide related research: (I) Materials & Engineering, (II) Food & Nutrition, (III) Biomedical Applications, (IV) Chemistry, Biology & Physics, and (V) Skills & Education. Each section summarizes the state of research, identifies challenges that are currently faced, project achievements and developments that are expected in the upcoming 20 years, and finally provides outlines on how future research activities need to evolve.
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| 6. |
- Grünig, Marc, et al.
(author)
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A harmonized database of European forest simulations under climate change
- 2024
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In: Data in Brief. - 2352-3409. ; 54
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Journal article (peer-reviewed)abstract
- Process-based forest models combine biological, physical, and chemical process understanding to simulate forest dynamics as an emergent property of the system. As such, they are valuable tools to investigate the effects of climate change on forest ecosystems. Specifically, they allow testing of hypotheses regarding long-term ecosystem dynamics and provide means to assess the impacts of climate scenarios on future forest development. As a consequence, numerous local-scale simulation studies have been conducted over the past decades to assess the impacts of climate change on forests. These studies apply the best available models tailored to local conditions, parameterized and evaluated by local experts. However, this treasure trove of knowledge on climate change responses remains underexplored to date, as a consistent and harmonized dataset of local model simulations is missing. Here, our objectives were (i) to compile existing local simulations on forest development under climate change in Europe in a common database, (ii) to harmonize them to a common suite of output variables, and (iii) to provide a standardized vector of auxiliary environmental variables for each simulated location to aid subsequent investigations. Our dataset of European stand- and landscape-level forest simulations contains over 1.1 million simulation runs representing 135 million simulation years for more than 13,000 unique locations spread across Europe. The data were harmonized to consistently describe forest development in terms of stand structure (dominant height), composition (dominant species, admixed species), and functioning (leaf area index). Auxiliary variables provided include consistent daily climate information (temperature, precipitation, radiation, vapor pressure deficit) as well as information on local site conditions (soil depth, soil physical properties, soil water holding capacity, plant-available nitrogen). The present dataset facilitates analyses across models and locations, with the aim to better harness the valuable information contained in local simulations for large-scale policy support, and for fostering a deeper understanding of the effects of climate change on forest ecosystems in Europe.
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| 7. |
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| 8. |
- Merkl, Philipp, et al.
(author)
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Proximity control of interlayer exciton-phonon hybridization in van der Waals heterostructures
- 2021
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In: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723 .- 2041-1723. ; 12:1
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Journal article (peer-reviewed)abstract
- Van der Waals stacking has provided unprecedented flexibility in shaping many-body interactions by controlling electronic quantum confinement and orbital overlap. Theory has predicted that also electron-phonon coupling critically influences the quantum ground state of low-dimensional systems. Here we introduce proximity-controlled strong-coupling between Coulomb correlations and lattice dynamics in neighbouring van der Waals materials, creating new electrically neutral hybrid eigenmodes. Specifically, we explore how the internal orbital 1s-2p transition of Coulomb-bound electron-hole pairs in monolayer tungsten diselenide resonantly hybridizes with lattice vibrations of a polar capping layer of gypsum, giving rise to exciton-phonon mixed eigenmodes, called excitonic Lyman polarons. Tuning orbital exciton resonances across the vibrational resonances, we observe distinct anticrossing and polarons with adjustable exciton and phonon compositions. Such proximity-induced hybridization can be further controlled by quantum designing the spatial wavefunction overlap of excitons and phonons, providing a promising new strategy to engineer novel ground states of two-dimensional systems. Here, the authors demonstrate proximity-controlled strong-coupling between Coulomb correlations and lattice dynamics in neighbouring van der Waals materials (WSe2 and a gypsum layer), creating electrically neutral hybrid exciton-phonon eigenmodes called excitonic Lyman polarons.
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| 9. |
- Merkl, Philipp, et al.
(author)
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Ultrafast Transition from Intra- to Interlayer Exciton Phases in a Van Der Waals Heterostructure
- 2019
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In: Optics InfoBase Conference Papers. - 2162-2701. - 9781943580576 ; Part F127-CLEO_AT 2019
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Conference paper (peer-reviewed)abstract
- The binding energy of interlayer excitons is measured by revealing a novel 1s-2p resonance in the mid infrared. Intralayer excitons transform directly into interlayer species via ultrafast electron tunneling strongly influenced by the stacking angle. (C) 2019 The Author(s)
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| 10. |
- Mooshammer, Fabian, et al.
(author)
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Excitons in twisted van der Waals bilayers: Internal structure and ultrafast dynamics
- 2020
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In: 2020 45TH INTERNATIONAL CONFERENCE ON INFRARED, MILLIMETER, AND TERAHERTZ WAVES (IRMMW-THZ). - 2162-2027.
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Conference paper (peer-reviewed)abstract
- By probing internal 1s-2p transitions with phaselocked mid-infrared pulses, we reveal the internal structure and binding energy of photo-generated excitons in transition metal dichalcogenide bilayers. Furthermore, we trace how the twist angle precisely controls the ultrafast formation of interlayer excitons and tunes excitonic hybridization in hetero- and homobilayers, respectively.
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