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Sidiropoulos TPH, Di Palo N, Rivas DE, Summers A, Severino S, Reduzzi M, Biegert J. Enhanced optical conductivity and many-body effects in strongly-driven photo-excited semi-metallic graphite. Nat Commun 2023; 14:7407. [PMID: 37973799 PMCID: PMC10654445 DOI: 10.1038/s41467-023-43191-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Accepted: 11/02/2023] [Indexed: 11/19/2023] Open
Abstract
The excitation of quasi-particles near the extrema of the electronic band structure is a gateway to electronic phase transitions in condensed matter. In a many-body system, quasi-particle dynamics are strongly influenced by the electronic single-particle structure and have been extensively studied in the weak optical excitation regime. Yet, under strong optical excitation, where light fields coherently drive carriers, the dynamics of many-body interactions that can lead to new quantum phases remain largely unresolved. Here, we induce such a highly non-equilibrium many-body state through strong optical excitation of charge carriers near the van Hove singularity in graphite. We investigate the system's evolution into a strongly-driven photo-excited state with attosecond soft X-ray core-level spectroscopy. We find an enhancement of the optical conductivity of nearly ten times the quantum conductivity and pinpoint it to carrier excitations in flat bands. This interaction regime is robust against carrier-carrier interaction with coherent optical phonons acting as an attractive force reminiscent of superconductivity. The strongly-driven non-equilibrium state is markedly different from the single-particle structure and macroscopic conductivity and is a consequence of the non-adiabatic many-body state.
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Affiliation(s)
- T P H Sidiropoulos
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
- Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, 12489, Berlin, Germany.
| | - N Di Palo
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain
| | - D E Rivas
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain
| | - A Summers
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain
| | - S Severino
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain
| | - M Reduzzi
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain
| | - J Biegert
- ICFO - Institut de Ciencies Fotoniques, The Barcelona Institute of Science and Technology, 08860, Barcelona, Spain.
- ICREA - Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
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2
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Girotto N, Novko D. Dynamical Phonons Following Electron Relaxation Stages in Photoexcited Graphene. J Phys Chem Lett 2023; 14:8709-8716. [PMID: 37735110 DOI: 10.1021/acs.jpclett.3c01905] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/23/2023]
Abstract
Ultrafast electron-phonon relaxation dynamics in graphene hides many distinct phenomena, such as hot phonon generation, dynamical Kohn anomalies, and phonon decoupling, yet it still remains largely unexplored. Here, we unravel intricate mechanisms governing the vibrational relaxation and phonon dressing in graphene at a highly nonequilibrium state by means of first-principles techniques. We calculate dynamical phonon spectral functions and momentum-resolved line widths for various stages of electron relaxation and find photoinduced phonon hardening, overall increase of relaxation rate and nonadiabaticity, as well as phonon gain. Namely, the initial stage of photoexcitation is found to be governed by strong phonon anomalies of finite-momentum optical modes along with incoherent phonon production. The population inversion state, on the other hand, allows the production of coherent and strongly coupled phonon modes. Our research provides vital insights into the electron-phonon coupling phenomena in graphene and serves as a foundation for exploring nonequilibrium phonon dressing in materials where ordered states and phase transitions can be induced by photoexcitation.
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Affiliation(s)
- Nina Girotto
- Centre for Advanced Laser Techniques, Institute of Physics, 10000 Zagreb, Croatia
| | - Dino Novko
- Centre for Advanced Laser Techniques, Institute of Physics, 10000 Zagreb, Croatia
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3
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Wang G, Wang K, McEvoy N, Bai Z, Cullen CP, Murphy CN, McManus JB, Magan JJ, Smith CM, Duesberg GS, Kaminer I, Wang J, Blau WJ. Ultrafast Carrier Dynamics and Bandgap Renormalization in Layered PtSe 2. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2019; 15:e1902728. [PMID: 31276302 DOI: 10.1002/smll.201902728] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Indexed: 06/09/2023]
Abstract
Carrier interactions in 2D nanostructures are of central importance not only in condensed-matter physics but also for a wide range of optoelectronic and photonic applications. Here, new insights into the behavior of photoinduced carriers in layered platinum diselenide (PtSe2 ) through ultrafast time-resolved pump-probe and nonlinear optical measurements are presented. The measurements reveal the temporal evolution of carrier relaxation, chemical potential and bandgap renormalization in PtSe2 . These results imply that few-layer PtSe2 has a semiconductor-like carrier relaxation instead of a metal-like one. The relaxation follows a triple-exponential decay process and exhibits thickness-dependent relaxation times. This occurs along with a band-filling effect, which can be controlled based on the number of layers and may be applied in saturable absorption for generating ultrafast laser pulses. The findings may provide means to study many-body physics in 2D materials as well as potentially leading to applications in the field of optoelectronics and ultrafast photonics.
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Affiliation(s)
- Gaozhong Wang
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - Kangpeng Wang
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
- Department of Electrical Engineering and Solid-State Institute, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Niall McEvoy
- School of Chemistry and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - Zhengyuan Bai
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - Conor P Cullen
- School of Chemistry and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - Conor N Murphy
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - John B McManus
- School of Chemistry and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | - John J Magan
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
| | | | - Georg S Duesberg
- Institute of Physics, EIT 2, Faculty of Electrical Engineering and Information Technology, Universität der Bundeswehr München, Werner-Heisenberg-Weg 39, 85577, Neubiberg, Germany
| | - Ido Kaminer
- Department of Electrical Engineering and Solid-State Institute, Technion-Israel Institute of Technology, Haifa, 32000, Israel
| | - Jun Wang
- Laboratory of Micro-Nano Photonic and Optoelectronic Materials and Devices, Key Laboratory of Materials for High-Power Laser, Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences & CAS Center for Excellence in Ultra-intense Laser Science, Shanghai, 201800, P. R. China
| | - Werner J Blau
- School of Physics and AMBER, Trinity College Dublin, Dublin 2, Ireland
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4
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Tan S, Dai Y, Zhang S, Liu L, Zhao J, Petek H. Coherent Electron Transfer at the Ag/Graphite Heterojunction Interface. PHYSICAL REVIEW LETTERS 2018; 120:126801. [PMID: 29694071 DOI: 10.1103/physrevlett.120.126801] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2017] [Indexed: 06/08/2023]
Abstract
Charge transfer in transduction of light to electrical or chemical energy at heterojunctions of metals with semiconductors or semimetals is believed to occur by photogenerated hot electrons in metal undergoing incoherent internal photoemission through the heterojunction interface. Charge transfer, however, can also occur coherently by dipole coupling of electronic bands at the heterojunction interface. Microscopic physical insights into how transfer occurs can be elucidated by following the coherent polarization of the donor and acceptor states on the time scale of electronic dephasing. By time-resolved multiphoton photoemission spectroscopy (MPP), we investigate the coherent electron transfer from an interface state that forms upon chemisorption of Ag nanoclusters onto graphite to a σ symmetry interlayer band of graphite. Multidimensional MPP spectroscopy reveals a resonant two-photon transition, which dephases within 10 fs completing the coherent transfer.
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Affiliation(s)
- Shijing Tan
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Yanan Dai
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Shengmin Zhang
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
| | - Liming Liu
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Jin Zhao
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
- ICQD/Hefei National Laboratory for Physical Sciences at the Microscale, and Key Laboratory of Strongly-Coupled Quantum Matter Physics, Chinese Academy of Sciences, and Department of Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
- Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China, Hefei, Anhui 230026, China
| | - Hrvoje Petek
- Department of Physics and Astronomy and Pittsburgh Quantum Institute, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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5
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Mor S, Herzog M, Golež D, Werner P, Eckstein M, Katayama N, Nohara M, Takagi H, Mizokawa T, Monney C, Stähler J. Ultrafast Electronic Band Gap Control in an Excitonic Insulator. PHYSICAL REVIEW LETTERS 2017; 119:086401. [PMID: 28952776 DOI: 10.1103/physrevlett.119.086401] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/10/2017] [Indexed: 06/07/2023]
Abstract
We report on the nonequilibrium dynamics of the electronic structure of the layered semiconductor Ta_{2}NiSe_{5} investigated by time- and angle-resolved photoelectron spectroscopy. We show that below the critical excitation density of F_{C}=0.2 mJ cm^{-2}, the band gap narrows transiently, while it is enhanced above F_{C}. Hartree-Fock calculations reveal that this effect can be explained by the presence of the low-temperature excitonic insulator phase of Ta_{2}NiSe_{5}, whose order parameter is connected to the gap size. This work demonstrates the ability to manipulate the band gap of Ta_{2}NiSe_{5} with light on the femtosecond time scale.
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Affiliation(s)
- Selene Mor
- Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
| | - Marc Herzog
- Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
- Institute for Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam, Germany
| | - Denis Golež
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Philipp Werner
- Department of Physics, University of Fribourg, 1700 Fribourg, Switzerland
| | - Martin Eckstein
- Department of Physics, University of Erlangen-Nürnberg, Staudtstrasse 7-B2, 91058 Erlangen, Germany
| | - Naoyuki Katayama
- Department of Physical Science and Engineering, Nagoya University, 464-8603 Nagoya, Japan
| | - Minoru Nohara
- Research Institute for Interdisciplinary Science, Okayama University, Okayama 700-8530, Japan
| | - Hide Takagi
- Max Planck Institute for Solid State Research, 70569 Stuttgart, Germany
- Department of Physics, University of Tokyo, 113-8654 Tokyo, Japan
| | - Takashi Mizokawa
- Department of Applied Physics, Waseda University, 169-8555 Tokyo, Japan
| | - Claude Monney
- Institute of Physics, University of Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland
| | - Julia Stähler
- Fritz-Haber-Institut der MPG, Faradayweg 4-6, 14195 Berlin, Germany
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Pennacchio F, Vanacore GM, Mancini GF, Oppermann M, Jayaraman R, Musumeci P, Baum P, Carbone F. Design and implementation of an optimal laser pulse front tilting scheme for ultrafast electron diffraction in reflection geometry with high temporal resolution. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2017; 4:044032. [PMID: 28713841 PMCID: PMC5491388 DOI: 10.1063/1.4991483] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2017] [Accepted: 06/21/2017] [Indexed: 06/07/2023]
Abstract
Ultrafast electron diffraction is a powerful technique to investigate out-of-equilibrium atomic dynamics in solids with high temporal resolution. When diffraction is performed in reflection geometry, the main limitation is the mismatch in group velocity between the overlapping pump light and the electron probe pulses, which affects the overall temporal resolution of the experiment. A solution already available in the literature involved pulse front tilt of the pump beam at the sample, providing a sub-picosecond time resolution. However, in the reported optical scheme, the tilted pulse is characterized by a temporal chirp of about 1 ps at 1 mm away from the centre of the beam, which limits the investigation of surface dynamics in large crystals. In this paper, we propose an optimal tilting scheme designed for a radio-frequency-compressed ultrafast electron diffraction setup working in reflection geometry with 30 keV electron pulses containing up to 105 electrons/pulse. To characterize our scheme, we performed optical cross-correlation measurements, obtaining an average temporal width of the tilted pulse lower than 250 fs. The calibration of the electron-laser temporal overlap was obtained by monitoring the spatial profile of the electron beam when interacting with the plasma optically induced at the apex of a copper needle (plasma lensing effect). Finally, we report the first time-resolved results obtained on graphite, where the electron-phonon coupling dynamics is observed, showing an overall temporal resolution in the sub-500 fs regime. The successful implementation of this configuration opens the way to directly probe structural dynamics of low-dimensional systems in the sub-picosecond regime, with pulsed electrons.
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Affiliation(s)
- Francesco Pennacchio
- Laboratory for Ultrafast Microscopy and Electron Scattering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Giovanni M Vanacore
- Laboratory for Ultrafast Microscopy and Electron Scattering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Giulia F Mancini
- JILA, University of Colorado, 440 UCB, Boulder, Colorado 80309-0440, USA
| | - Malte Oppermann
- Laboratory of Ultrafast Spectroscopy, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Rajeswari Jayaraman
- Laboratory for Ultrafast Microscopy and Electron Scattering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
| | - Pietro Musumeci
- Particle Beam Physics Laboratory, Department of Physics and Astronomy, UCLA, Los Angeles, California 90095, USA
| | - Peter Baum
- Ludwig-Maximilians-Universität München, Am Coulombwall 1, 85748 Garching, Germany
| | - Fabrizio Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering, École Polytechnique Fédérale de Lausanne, CH-1015 Lausanne, Switzerland
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7
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Shen MJ, Liang TL, Song YQ, Xu LJ, Hao X, Gong HY. Substrate-induced adjustment of “slipped” π– π stacking: en route to obtain 1D sandwich chain and higher order self-assembly supramolecular structures in solid state. Supramol Chem 2017. [DOI: 10.1080/10610278.2016.1161196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Meng-Jie Shen
- Department of Chemistry, Renmin University of China, Beijing, P.R. China
| | - Tong-Ling Liang
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China
| | - Yue-Qiang Song
- Department of Information Engineering, Qingdao Harbour Vacational & Technical College, Qingdao, P.R. China
| | - Li-Jin Xu
- Department of Chemistry, Renmin University of China, Beijing, P.R. China
| | - Xiang Hao
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, P.R. China
| | - Han-Yuan Gong
- College of Chemistry, Beijing Normal University, Beijing, P.R. China
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8
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Optically induced effective mass renormalization: the case of graphite image potential states. Sci Rep 2016; 6:35318. [PMID: 27739489 PMCID: PMC5064354 DOI: 10.1038/srep35318] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 09/26/2016] [Indexed: 01/24/2023] Open
Abstract
Many-body interactions with the underlying bulk electrons determine the properties of confined electronic states at the surface of a metal. Using momentum resolved nonlinear photoelectron spectroscopy we show that one can tailor these many-body interactions in graphite, leading to a strong renormalization of the dispersion and linewidth of the image potential state. These observations are interpreted in terms of a basic self-energy model, and may be considered as exemplary for optically induced many-body interactions.
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9
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van der Veen RM, Penfold TJ, Zewail AH. Ultrafast core-loss spectroscopy in four-dimensional electron microscopy. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:024302. [PMID: 26798793 PMCID: PMC4711615 DOI: 10.1063/1.4916897] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2015] [Accepted: 03/23/2015] [Indexed: 05/06/2023]
Abstract
We demonstrate ultrafast core-electron energy-loss spectroscopy in four-dimensional electron microscopy as an element-specific probe of nanoscale dynamics. We apply it to the study of photoexcited graphite with femtosecond and nanosecond resolutions. The transient core-loss spectra, in combination with ab initio molecular dynamics simulations, reveal the elongation of the carbon-carbon bonds, even though the overall behavior is a contraction of the crystal lattice. A prompt energy-gap shrinkage is observed on the picosecond time scale, which is caused by local bond length elongation and the direct renormalization of band energies due to temperature-dependent electron-phonon interactions.
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Affiliation(s)
| | - Thomas J Penfold
- SwissFEL, Paul Scherrer Institut , 5232 Villigen PSI, Switzerland
| | - Ahmed H Zewail
- Physical Biology Center for Ultrafast Science and Technology, Arthur Amos Noyes Laboratory of Chemical Physics, California Institute of Technology , Pasadena, California 91125, USA
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10
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Carbone F. Dynamics deep from the core. STRUCTURAL DYNAMICS (MELVILLE, N.Y.) 2015; 2:020601. [PMID: 26798787 PMCID: PMC4711669 DOI: 10.1063/1.4918727] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/06/2015] [Accepted: 04/10/2015] [Indexed: 06/05/2023]
Abstract
In van der Veen et al., [Struct. Dyn. 2, 024302 (2015)], femtosecond and nanosecond electron energy loss spectroscopy of deep core-levels are demonstrated. These results pave the way to the investigation of materials and molecules with combined energy, time, and spatial resolution in a transmission electron microscope. Furthermore, the authors elucidate the role of the electron phonon coupling in the band-gap renormalization that takes place in graphite upon photo-excitation.
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Affiliation(s)
- F Carbone
- Laboratory for Ultrafast Microscopy and Electron Scattering (LUMES), Institute of Condensed Matter Physics (ICMP), École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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