1
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Koutenský P, Slobodeniuk A, Bartoš M, Trojánek F, Malý P, Kozák M. Ultrafast Dynamics of Valley-Polarized Excitons in WSe 2 Monolayer Studied by Few-Cycle Laser Pulses. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1207. [PMID: 37049301 PMCID: PMC10096652 DOI: 10.3390/nano13071207] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 03/20/2023] [Accepted: 03/27/2023] [Indexed: 06/19/2023]
Abstract
We report on the experimental investigation of the ultrafast dynamics of valley-polarized excitons in monolayer WSe2 using transient reflection spectroscopy with few-cycle laser pulses with 7 fs duration. We observe that at room temperature, the anisotropic valley population of excitons decays on two different timescales. The shorter decay time of approximately 120 fs is related to the initial hot exciton relaxation related to the fast direct recombination of excitons from the radiative zone, while the slower picosecond dynamics corresponds to valley depolarization induced by Coloumb exchange-driven transitions of excitons between two inequivalent valleys.
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Affiliation(s)
- Petr Koutenský
- Department of Chemical Physics and Optics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 3, 121 16 Prague, Czech Republic
| | - Artur Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
| | - Miroslav Bartoš
- Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - František Trojánek
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
| | - Petr Malý
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
| | - Martin Kozák
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 121 16 Prague, Czech Republic
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2
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Popert A, Shimazaki Y, Kroner M, Watanabe K, Taniguchi T, Imamoğlu A, Smoleński T. Optical Sensing of Fractional Quantum Hall Effect in Graphene. NANO LETTERS 2022; 22:7363-7369. [PMID: 36124418 PMCID: PMC9523700 DOI: 10.1021/acs.nanolett.2c02000] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2022] [Revised: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Graphene and its heterostructures provide a unique and versatile playground for explorations of strongly correlated electronic phases, ranging from unconventional fractional quantum Hall (FQH) states in a monolayer system to a plethora of superconducting and insulating states in twisted bilayers. However, the access to those fascinating phases has been thus far entirely restricted to transport techniques, due to the lack of a robust energy bandgap that makes graphene hard to access optically. Here we demonstrate an all-optical, noninvasive spectroscopic tool for probing electronic correlations in graphene using excited Rydberg excitons in an adjacent transition metal dichalcogenide monolayer. These excitons are highly susceptible to the compressibility of graphene electrons, allowing us to detect the formation of odd-denominator FQH states at high magnetic fields. Owing to its submicron spatial resolution, the technique we demonstrate circumvents spatial inhomogeneities and paves the way for optical studies of correlated states in optically inactive atomically thin materials.
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Affiliation(s)
- Alexander Popert
- Institute
for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Yuya Shimazaki
- Institute
for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
- Center
for Emergent Matter Science, RIKEN, Wako, Saitama 351-0198, Japan
| | - Martin Kroner
- Institute
for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, Tsukuba, Ibaraki 305-0044, Japan
| | - Ataç Imamoğlu
- Institute
for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
| | - Tomasz Smoleński
- Institute
for Quantum Electronics, ETH Zürich, CH-8093 Zürich, Switzerland
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3
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Usman A, Adel Aly M, Masenda H, Thompson JJP, Gunasekera SM, Mucha-Kruczyński M, Brem S, Malic E, Koch M. Enhanced excitonic features in an anisotropic ReS 2/WSe 2 heterostructure. NANOSCALE 2022; 14:10851-10861. [PMID: 35838641 DOI: 10.1039/d2nr01973f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Two-dimensional (2D) semiconductors have opened new horizons for future optoelectronic applications through efficient light-matter and many-body interactions at quantum level. Anisotropic 2D materials like rhenium disulphide (ReS2) present a new class of materials with polarized excitonic resonances. Here, we demonstrate a WSe2/ReS2 heterostructure which exhibits a significant photoluminescence quenching at room temperature as well as at low temperatures. This indicates an efficient charge transfer due to the electron-hole exchange interaction. The band alignment of two materials suggests that electrons optically injected into WSe2 are transferred to ReS2. Polarization resolved luminescence measurements reveal two additional polarization-sensitive exciton peaks in ReS2 in addition to the two conventional exciton resonances X1 and X2. Furthermore, for ReS2 we observe two charged excitons (trions) with binding energies of 18 meV and 15 meV, respectively. The bi-excitons of WSe2 become polarization sensitive and inherit polarizing properties from the underlying ReS2 layers, which act as patterned substrates for top layer. Overall, our findings provide a better understanding of optical signatures in 2D anisotropic materials.
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Affiliation(s)
- Arslan Usman
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
- Department of Physics, COMSATS University Islamabad-Lahore-Campus, Pakistan
| | - M Adel Aly
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
- Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566, Egypt
| | - Hilary Masenda
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
- School of Physics, University of the Witwatersrand, 2050 Johannesburg, South Africa
| | - Joshua J P Thompson
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
| | | | - Marcin Mucha-Kruczyński
- Department of Physics, University of Bath, Claverton Down, Bath BA2 7AY, UK
- Centre for Nanoscience and Nanotechnology, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Samuel Brem
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
| | - Ermin Malic
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
| | - Martin Koch
- Department of Physics and Materials Sciences Centre, Philipps-Universität Marburg, Marburg 35032, Germany.
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4
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Bieniek M, Sadecka K, Szulakowska L, Hawrylak P. Theory of Excitons in Atomically Thin Semiconductors: Tight-Binding Approach. NANOMATERIALS (BASEL, SWITZERLAND) 2022; 12:1582. [PMID: 35564291 PMCID: PMC9104105 DOI: 10.3390/nano12091582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Revised: 04/24/2022] [Accepted: 04/26/2022] [Indexed: 02/01/2023]
Abstract
Atomically thin semiconductors from the transition metal dichalcogenide family are materials in which the optical response is dominated by strongly bound excitonic complexes. Here, we present a theory of excitons in two-dimensional semiconductors using a tight-binding model of the electronic structure. In the first part, we review extensive literature on 2D van der Waals materials, with particular focus on their optical response from both experimental and theoretical points of view. In the second part, we discuss our ab initio calculations of the electronic structure of MoS2, representative of a wide class of materials, and review our minimal tight-binding model, which reproduces low-energy physics around the Fermi level and, at the same time, allows for the understanding of their electronic structure. Next, we describe how electron-hole pair excitations from the mean-field-level ground state are constructed. The electron-electron interactions mix the electron-hole pair excitations, resulting in excitonic wave functions and energies obtained by solving the Bethe-Salpeter equation. This is enabled by the efficient computation of the Coulomb matrix elements optimized for two-dimensional crystals. Next, we discuss non-local screening in various geometries usually used in experiments. We conclude with a discussion of the fine structure and excited excitonic spectra. In particular, we discuss the effect of band nesting on the exciton fine structure; Coulomb interactions; and the topology of the wave functions, screening and dielectric environment. Finally, we follow by adding another layer and discuss excitons in heterostructures built from two-dimensional semiconductors.
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Affiliation(s)
- Maciej Bieniek
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
- Institut für Theoretische Physik und Astrophysik, Universität Würzburg, 97074 Würzburg, Germany
| | - Katarzyna Sadecka
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
- Department of Theoretical Physics, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Ludmiła Szulakowska
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
| | - Paweł Hawrylak
- Department of Physics, University of Ottawa, Ottawa, ON K1N 6N5, Canada; (K.S.); (L.S.); (P.H.)
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5
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Grzeszczyk M, Olkowska-Pucko K, Nogajewski K, Watanabe K, Taniguchi T, Kossacki P, Babiński A, Molas MR. Exposing the trion's fine structure by controlling the carrier concentration in hBN-encapsulated MoS 2. NANOSCALE 2021; 13:18726-18733. [PMID: 34739017 DOI: 10.1039/d1nr03855a] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Atomically thin materials, like semiconducting transition metal dichalcogenides, are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. In this work, high-quality van der Waals heterostructures assembled from hBN-encapsulated monolayer MoS2 are studied with the aid of photoluminescence, photoluminescence excitation, and reflectance contrast experiments. We demonstrate that carrier concentration in MoS2 monolayers, arising from charge transfer from impurities in the substrate, can be significantly tuned within one order of magnitude by the modification of the bottom hBN flake thickness. The studied structures, characterized by spectral lines with linewidths approaching the narrow homogeneously broadened limit enabled observations of subtle optical and spin-valley properties of excitonic complexes. Our results allowed us to resolve three optically-active negatively charged excitons in MoS2 monolayers, which are assigned to the intravalley singlet, intervalley singlet, and intervalley triplet states.
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Affiliation(s)
- Magdalena Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Katarzyna Olkowska-Pucko
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Karol Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 305-0044, Japan
| | - Piotr Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Adam Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
| | - Maciej R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland.
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6
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Shan H, Lackner L, Han B, Sedov E, Rupprecht C, Knopf H, Eilenberger F, Beierlein J, Kunte N, Esmann M, Yumigeta K, Watanabe K, Taniguchi T, Klembt S, Höfling S, Kavokin AV, Tongay S, Schneider C, Antón-Solanas C. Spatial coherence of room-temperature monolayer WSe 2 exciton-polaritons in a trap. Nat Commun 2021; 12:6406. [PMID: 34737328 PMCID: PMC8569157 DOI: 10.1038/s41467-021-26715-9] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 09/21/2021] [Indexed: 11/09/2022] Open
Abstract
The emergence of spatial and temporal coherence of light emitted from solid-state systems is a fundamental phenomenon intrinsically aligned with the control of light-matter coupling. It is canonical for laser oscillation, emerges in the superradiance of collective emitters, and has been investigated in bosonic condensates of thermalized light, as well as exciton-polaritons. Our room temperature experiments show the strong light-matter coupling between microcavity photons and excitons in atomically thin WSe2. We evidence the density-dependent expansion of spatial and temporal coherence of the emitted light from the spatially confined system ground-state, which is accompanied by a threshold-like response of the emitted light intensity. Additionally, valley-physics is manifested in the presence of an external magnetic field, which allows us to manipulate K and K' polaritons via the valley-Zeeman-effect. Our findings validate the potential of atomically thin crystals as versatile components of coherent light-sources, and in valleytronic applications at room temperature.
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Affiliation(s)
- Hangyong Shan
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany.
| | - Lukas Lackner
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany
| | - Bo Han
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany
| | - Evgeny Sedov
- Key Laboratory for Quantum Materials of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.,Vladimir State University named after A. G. and N. G. Stoletovs, Gorky str. 87, 600000, Vladimir, Russia
| | - Christoph Rupprecht
- Technische Physik, Universität Würzburg, D-97074, Würzburg, Am Hubland, Germany
| | - Heiko Knopf
- Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University, 07745, Jena, Germany.,Fraunhofer-Institute for Applied Optics and Precision Engineering IOF, 07745, Jena, Germany.,Max Planck School of Photonics, 07745, Jena, Germany
| | - Falk Eilenberger
- Institute of Applied Physics, Abbe Center of Photonics, Friedrich Schiller University, 07745, Jena, Germany.,Fraunhofer-Institute for Applied Optics and Precision Engineering IOF, 07745, Jena, Germany.,Max Planck School of Photonics, 07745, Jena, Germany
| | - Johannes Beierlein
- Technische Physik, Universität Würzburg, D-97074, Würzburg, Am Hubland, Germany
| | - Nils Kunte
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany
| | - Martin Esmann
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany
| | - Kentaro Yumigeta
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona, 85287, USA
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba, 305-0044, Japan
| | - Sebastian Klembt
- Technische Physik, Universität Würzburg, D-97074, Würzburg, Am Hubland, Germany
| | - Sven Höfling
- Technische Physik, Universität Würzburg, D-97074, Würzburg, Am Hubland, Germany
| | - Alexey V Kavokin
- Key Laboratory for Quantum Materials of Zhejiang Province, School of Science, Westlake University, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.,Institute of Natural Sciences, Westlake Institute for Advanced Study, 18 Shilongshan Road, Hangzhou, 310024, Zhejiang Province, People's Republic of China.,Physics and Astronomy, University of Southampton, Highfield, SO171BJ, Southampton, United Kingdom
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport, and Energy, Arizona State University, Tempe, Arizona, 85287, USA.
| | - Christian Schneider
- Institute of Physics, Carl von Ossietzky University, 26129, Oldenburg, Germany.
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7
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Liu E, van Baren J, Lu Z, Taniguchi T, Watanabe K, Smirnov D, Chang YC, Lui CH. Exciton-polaron Rydberg states in monolayer MoSe 2 and WSe 2. Nat Commun 2021; 12:6131. [PMID: 34675213 PMCID: PMC8531338 DOI: 10.1038/s41467-021-26304-w] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Accepted: 09/28/2021] [Indexed: 11/18/2022] Open
Abstract
Exciton polaron is a hypothetical many-body quasiparticle that involves an exciton dressed with a polarized electron-hole cloud in the Fermi sea. It has been evoked to explain the excitonic spectra of charged monolayer transition metal dichalcogenides, but the studies were limited to the ground state. Here we measure the reflection and photoluminescence of monolayer MoSe2 and WSe2 gating devices encapsulated by boron nitride. We observe gate-tunable exciton polarons associated with the 1 s–3 s exciton Rydberg states. The ground and excited exciton polarons exhibit comparable energy redshift (15~30 meV) from their respective bare excitons. The robust excited states contradict the trion picture because the trions are expected to dissociate in the excited states. When the Fermi sea expands, we observe increasingly severe suppression and steep energy shift from low to high exciton-polaron Rydberg states. Their gate-dependent energy shifts go beyond the trion description but match our exciton-polaron theory. Our experiment and theory demonstrate the exciton-polaron nature of both the ground and excited excitonic states in charged monolayer MoSe2 and WSe2. An exciton polaron is a quasiparticle composed of an exciton dressed with an electron-hole cloud, and this concept has been used to explain the ground excitonic states in charged monolayer transition metal dichalcogenides. Here the authors present experimental and theoretical evidence of exciton-polaron Rydberg states in monolayer MoSe2 and WSe2.
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Affiliation(s)
- Erfu Liu
- Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA
| | - Jeremiah van Baren
- Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA
| | - Zhengguang Lu
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA.,Department of Physics, Florida State University, Tallahassee, FL, 32310, USA
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki, 305-0044, Japan
| | - Kenji Watanabe
- National Institute for Materials Science, 1-1 Namiki Tsukuba, Ibaraki, 305-0044, Japan
| | - Dmitry Smirnov
- National High Magnetic Field Laboratory, Tallahassee, FL, 32310, USA
| | - Yia-Chung Chang
- Research Center for Applied Sciences, Academia Sinica, Taipei, 11529, Taiwan.
| | - Chun Hung Lui
- Department of Physics and Astronomy, University of California, Riverside, CA, 92521, USA.
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8
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Zalipaev VV, Kuidin VV. Semiclassical approach for excitonic spectrum of Coulomb coupling between two Dirac particles. Proc Math Phys Eng Sci 2021. [DOI: 10.1098/rspa.2021.0098] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
The properties of the energy spectrum of excitons in monolayer transition metal dichalcogenides are investigated using a multiband model. In the multiband model, we use the excitonic Hamiltonian in the product base of the Dirac single-particle states at the conduction and valence band edges. Following the separation of variables, we decouple the corresponding energy eigenvalue system of the first-order ODE radial equations rigorously and solve the resulting second-order ODE self-consistently, using the finite difference method, thus we determine the energy eigenvalues of the discrete excitonic spectrum and the corresponding wave functions. We also developed a WKB approach to solve the same spectral problem in semiclassical approximation for the resulting ODE. We compare the results for the energy spectrum and the corresponding eigen-function forms for WS
2
and WSe
2
obtained by means of both methods. We also compare our results for the energy spectrum with other theoretical works for excitons, and with available experimental data.
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9
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Zinkiewicz M, Woźniak T, Kazimierczuk T, Kapuscinski P, Oreszczuk K, Grzeszczyk M, Bartoš M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Excitonic Complexes in n-Doped WS 2 Monolayer. NANO LETTERS 2021; 21:2519-2525. [PMID: 33683895 PMCID: PMC7995249 DOI: 10.1021/acs.nanolett.0c05021] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 02/22/2021] [Indexed: 05/25/2023]
Abstract
We investigate the origin of emission lines apparent in the low-temperature photoluminescence spectra of n-doped WS2 monolayer embedded in hexagonal BN layers using external magnetic fields and first-principles calculations. Apart from the neutral A exciton line, all observed emission lines are related to the negatively charged excitons. Consequently, we identify emissions due to both the bright (singlet and triplet) and dark (spin- and momentum-forbidden) negative trions as well as the phonon replicas of the latter optically inactive complexes. The semidark trions and negative biexcitons are distinguished. On the basis of their experimentally extracted and theoretically calculated g-factors, we identify three distinct families of emissions due to exciton complexes in WS2: bright, intravalley, and intervalley dark. The g-factors of the spin-split subbands in both the conduction and valence bands are also determined.
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Affiliation(s)
- Małgorzata Zinkiewicz
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Tomasz Woźniak
- Department
of Semiconductor Materials Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego
27, 50-370 Wrocław, Poland
| | - Tomasz Kazimierczuk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Piotr Kapuscinski
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
- Department
of Experimental Physics, Wrocław University
of Science and Technology, Wybrzeze Wyspianskiego 27, 50-370 Wrocław, Poland
| | - Kacper Oreszczuk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Magdalena Grzeszczyk
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Miroslav Bartoš
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
- Central
European Institute of Technology, Brno University
of Technology, Purkyňova
656/123, 612 00 Brno, Czech Republic
| | - Karol Nogajewski
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Kenji Watanabe
- Research
Center for Functional Materials, National
Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Takashi Taniguchi
- International
Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Clement Faugeras
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - Piotr Kossacki
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Marek Potemski
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
- Laboratoire
National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - Adam Babiński
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
| | - Maciej R. Molas
- Institute
of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland
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10
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Wang T, Li Z, Li Y, Lu Z, Miao S, Lian Z, Meng Y, Blei M, Taniguchi T, Watanabe K, Tongay S, Smirnov D, Zhang C, Shi SF. Giant Valley-Polarized Rydberg Excitons in Monolayer WSe 2 Revealed by Magneto-photocurrent Spectroscopy. NANO LETTERS 2020; 20:7635-7641. [PMID: 32902286 DOI: 10.1021/acs.nanolett.0c03167] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
A strong Coulomb interaction could lead to a strongly bound exciton with high-order excited states, similar to the Rydberg atom. The interaction of giant Rydberg excitons can be engineered for a correlated ordered exciton array with a Rydberg blockade, which is promising for realizing quantum simulation. Monolayer transition metal dichalcogenides, with their greatly enhanced Coulomb interaction, are an ideal platform to host the Rydberg excitons in two dimensions. Here, we employ helicity-resolved magneto-photocurrent spectroscopy to identify Rydberg exciton states up to 11s in monolayer WSe2. Notably, the radius of the Rydberg exciton at 11s can be as large as 214 nm, orders of magnitude larger than the 1s exciton. The giant valley-polarized Rydberg exciton not only provides an exciting platform to study the strong exciton-exciton interaction and nonlinear exciton response but also allows the investigation of the different interplay between the Coulomb interaction and Landau quantization, tunable from a low- to high-magnetic-field limit.
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Affiliation(s)
- Tianmeng Wang
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Zhipeng Li
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Yunmei Li
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Zhengguang Lu
- National High Magnetic Field Lab, Tallahassee, Florida 32310, United States
- Department of Physics, Florida State University, Tallahassee, Florida 32306, United States
| | - Shengnan Miao
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Zhen Lian
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Yuze Meng
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
| | - Mark Blei
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Takashi Taniguchi
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Sefaattin Tongay
- School for Engineering of Matter, Transport and Energy, Arizona State University, Tempe, Arizona 85287, United States
| | - Dmitry Smirnov
- National High Magnetic Field Lab, Tallahassee, Florida 32310, United States
| | - Chuanwei Zhang
- Department of Physics, The University of Texas at Dallas, Richardson, Texas 75080, United States
| | - Su-Fei Shi
- Department of Chemical and Biological Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
- Department of Electrical, Computer & Systems Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180, United States
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11
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Zinkiewicz M, Slobodeniuk AO, Kazimierczuk T, Kapuściński P, Oreszczuk K, Grzeszczyk M, Bartos M, Nogajewski K, Watanabe K, Taniguchi T, Faugeras C, Kossacki P, Potemski M, Babiński A, Molas MR. Neutral and charged dark excitons in monolayer WS 2. NANOSCALE 2020; 12:18153-18159. [PMID: 32853305 DOI: 10.1039/d0nr04243a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Low temperature and polarization resolved magneto-photoluminescence experiments are used to investigate the properties of dark excitons and dark trions in a monolayer of WS2 encapsulated in hexagonal BN (hBN). We find that this system is an n-type doped semiconductor and that dark trions dominate the emission spectrum. In line with previous studies on WSe2, we identify the Coulomb exchange interaction coupled neutral dark and grey excitons through their polarization properties, while an analogous effect is not observed for dark trions. Applying the magnetic field in both perpendicular and parallel configurations with respect to the monolayer plane, we determine the g-factor of dark trions to be g ∼ -8.6. Their decay rate is close to 0.5 ns, more than 2 orders of magnitude longer than that of bright excitons.
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Affiliation(s)
- M Zinkiewicz
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - A O Slobodeniuk
- Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University in Prague, Ke Karlovu 5, Praha 2 CZ-121 16, Czech Republic
| | - T Kazimierczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - P Kapuściński
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Department of Experimental Physics, Faculty of Fundamental Problems of Technology, Wrocław University of Science and Technology, ul. Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - K Oreszczuk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Grzeszczyk
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Bartos
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France and Central European Institute of Technology, Brno University of Technology, Purkyňova 656/123, 612 00 Brno, Czech Republic
| | - K Nogajewski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - K Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - T Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - C Faugeras
- Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - P Kossacki
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M Potemski
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland. and Laboratoire National des Champs Magnétiques Intenses, CNRS-UGA-UPS-INSA-EMFL, 25, avenue des Martyrs, 38042 Grenoble, France
| | - A Babiński
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
| | - M R Molas
- Institute of Experimental Physics, Faculty of Physics, University of Warsaw, ul. Pasteura 5, 02-093 Warsaw, Poland.
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12
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The effect of metallic substrates on the optical properties of monolayer MoSe 2. Sci Rep 2020; 10:4981. [PMID: 32188877 PMCID: PMC7080835 DOI: 10.1038/s41598-020-61673-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 02/26/2020] [Indexed: 11/21/2022] Open
Abstract
Atomically thin materials, like semiconducting transition metal dichalcogenides (S-TMDs), are highly sensitive to the environment. This opens up an opportunity to externally control their properties by changing their surroundings. Photoluminescence and reflectance contrast techniques are employed to investigate the effect of metallic substrates on optical properties of MoSe2 monolayer (ML). The optical spectra of MoSe2 MLs deposited on Pt, Au, Mo and Zr have distinctive metal-related lineshapes. In particular, a substantial variation in the intensity ratio and the energy separation between a negative trion and a neutral exciton is observed. It is shown that using metals as substrates affects the doping of S-TMD MLs. The explanation of the effect involves the Schottky barrier formation at the interface between the MoSe2 ML and the metallic substrates. The alignment of energy levels at the metal/semiconductor junction allows for the transfer of charge carriers between them. We argue that a proper selection of metallic substrates can be a way to inject appropriate types of carriers into the respective bands of S-TMDs.
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13
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Kapuściński P, Vaclavkova D, Grzeszczyk M, Slobodeniuk AO, Nogajewski K, Bartos M, Watanabe K, Taniguchi T, Faugeras C, Babiński A, Potemski M, Molas MR. Valley polarization of singlet and triplet trions in a WS2 monolayer in magnetic fields. Phys Chem Chem Phys 2020; 22:19155-19161. [DOI: 10.1039/d0cp02737e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Magnetic field induced valley polarization of carriers is substantially different for the absorption and emission response of a WS2 monolayer.
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14
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Arora A, Deilmann T, Reichenauer T, Kern J, Michaelis de Vasconcellos S, Rohlfing M, Bratschitsch R. Excited-State Trions in Monolayer WS_{2}. PHYSICAL REVIEW LETTERS 2019; 123:167401. [PMID: 31702327 DOI: 10.1103/physrevlett.123.167401] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Indexed: 05/16/2023]
Abstract
We discover an excited bound three-particle state, the 2s trion, appearing energetically below the 2s exciton in monolayer WS_{2}, using absorption spectroscopy and ab initio GW and Bethe-Salpeter equation calculations. The measured binding energy of the 2s trion (22 meV) is smaller compared to the 1s intravalley and intervalley trions (37 and 31 meV). With increasing temperature, the 1s and 2s trions transfer their oscillator strengths to the respective neutral excitons, establishing an optical fingerprint of trion-exciton resonance pairs. Our discovery underlines the importance of trions for the entire excitation spectrum of two-dimensional semiconductors.
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Affiliation(s)
- Ashish Arora
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Thorsten Deilmann
- Institute of Solid State Theory, Wilhelm-Klemm-Straße 10, University of Münster, 48149 Münster, Germany
| | - Till Reichenauer
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | - Johannes Kern
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
| | | | - Michael Rohlfing
- Institute of Solid State Theory, Wilhelm-Klemm-Straße 10, University of Münster, 48149 Münster, Germany
| | - Rudolf Bratschitsch
- Institute of Physics and Center for Nanotechnology, University of Münster, Wilhelm-Klemm-Straße 10, 48149 Münster, Germany
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15
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Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields. Nat Commun 2019; 10:4172. [PMID: 31519909 PMCID: PMC6744484 DOI: 10.1038/s41467-019-12180-y] [Citation(s) in RCA: 74] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 08/27/2019] [Indexed: 11/08/2022] Open
Abstract
In semiconductor physics, many essential optoelectronic material parameters can be experimentally revealed via optical spectroscopy in sufficiently large magnetic fields. For monolayer transition-metal dichalcogenide semiconductors, this field scale is substantial-tens of teslas or more-due to heavy carrier masses and huge exciton binding energies. Here we report absorption spectroscopy of monolayer [Formula: see text], and [Formula: see text] in very high magnetic fields to 91 T. We follow the diamagnetic shifts and valley Zeeman splittings of not only the exciton's [Formula: see text] ground state but also its excited [Formula: see text] Rydberg states. This provides a direct experimental measure of the effective (reduced) exciton masses and dielectric properties. Exciton binding energies, exciton radii, and free-particle bandgaps are also determined. The measured exciton masses are heavier than theoretically predicted, especially for Mo-based monolayers. These results provide essential and quantitative parameters for the rational design of opto-electronic van der Waals heterostructures incorporating 2D semiconductors.
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