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Yuan L, Zheng B, Zhao Q, Kempt R, Brumme T, Kuc AB, Ma C, Deng S, Pan A, Huang L. Strong Dipolar Repulsion of One-Dimensional Interfacial Excitons in Monolayer Lateral Heterojunctions. ACS NANO 2023; 17:15379-15387. [PMID: 37540827 DOI: 10.1021/acsnano.2c12903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/06/2023]
Abstract
Repulsive and long-range exciton-exciton interactions are crucial for the exploration of one-dimensional (1D) correlated quantum phases in the solid state. However, the experimental realization of nanoscale confinement of a 1D dipolar exciton has thus far been limited. Here, we demonstrate atomically precise lateral heterojunctions based at transitional-metal dichalcogenides (TMDCs) as a platform for 1D dipolar excitons. The dynamics and transport of the interfacial charge transfer excitons in a type II WSe2-WS1.16Se0.84 lateral heterostructure were spatially and temporally imaged using ultrafast transient reflection microscopy. The expansion of the exciton cloud driven by dipolar repulsion was found to be strongly density dependent and highly anisotropic. The interaction strength between the 1D excitons was determined to be ∼3.9 × 10-14 eV cm-2, corresponding to a dipolar length of 310 nm, which is a factor of 2-3 larger than the interlayer excitons at two-dimensional van der Waals vertical interfaces. These results suggest 1D dipolar excitons with large static in-plane dipole moments in lateral TMDC heterojunctions as an exciting system for investigating quantum many-body physics.
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Affiliation(s)
- Long Yuan
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
- Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui 230052, China
| | - Biyuan Zheng
- College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410012, China
| | - Qiuchen Zhao
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Roman Kempt
- Technische Universitat Dresden, 01062 Dresden, Germany
| | - Thomas Brumme
- Technische Universitat Dresden, 01062 Dresden, Germany
| | - Agnieszka B Kuc
- Helmholtz-Zentrum Dresden-Rossendorf, Abteilung Ressourcenökologie, Forschungsstelle Leipzig, Permoserstraße 15, 04318 Leipzig, Germany
| | - Chao Ma
- College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410012, China
| | - Shibin Deng
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
| | - Anlian Pan
- College of Materials Science and Engineering, Hunan University, Changsha, Hunan 410012, China
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, Changsha, Hunan 410012, China
- State Key Laboratory of Chemo/Biosensing and Chemometrics, Changsha, Hunan 410012, China
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, Indiana 47906, United States
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2
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Troue M, Figueiredo J, Sigl L, Paspalides C, Katzer M, Taniguchi T, Watanabe K, Selig M, Knorr A, Wurstbauer U, Holleitner AW. Extended Spatial Coherence of Interlayer Excitons in MoSe_{2}/WSe_{2} Heterobilayers. PHYSICAL REVIEW LETTERS 2023; 131:036902. [PMID: 37540866 DOI: 10.1103/physrevlett.131.036902] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 06/09/2023] [Indexed: 08/06/2023]
Abstract
We report on the spatial coherence of interlayer exciton ensembles as formed in MoSe_{2}/WSe_{2} heterostructures and characterized by point-inversion Michelson-Morley interferometry. Below 10 K, the measured spatial coherence length of the interlayer excitons reaches values equivalent to the lateral expansion of the exciton ensembles. In this regime, the light emission of the excitons turns out to be homogeneously broadened in energy with a high temporal coherence. At higher temperatures, both the spatial coherence length and the temporal coherence time decrease, most likely because of thermal processes. The presented findings point towards a spatially extended, coherent many-body state of interlayer excitons at low temperature.
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Affiliation(s)
- Mirco Troue
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Johannes Figueiredo
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Lukas Sigl
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Christos Paspalides
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
| | - Manuel Katzer
- Institute for Theoretical Physics, Nonlinear Optics and Quantum Electronics, Technical University of Berlin, 10623 Berlin, Germany
| | - Takashi Taniguchi
- Research Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Electronic and Optical Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Malte Selig
- Institute for Theoretical Physics, Nonlinear Optics and Quantum Electronics, Technical University of Berlin, 10623 Berlin, Germany
| | - Andreas Knorr
- Institute for Theoretical Physics, Nonlinear Optics and Quantum Electronics, Technical University of Berlin, 10623 Berlin, Germany
| | - Ursula Wurstbauer
- Institute of Physics, Münster University, Wilhelm-Klemm-Str. 10, 48149 Münster, Germany
| | - Alexander W Holleitner
- Walter Schottky Institute and Physics Department, Technical University of Munich, Am Coulombwall 4a, 85748 Garching, Germany
- Munich Center for Quantum Science and Technology (MCQST), Schellingstr. 4, 80799 Munich, Germany
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3
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Electrically tunable quantum confinement of neutral excitons. Nature 2022; 606:298-304. [PMID: 35614215 DOI: 10.1038/s41586-022-04634-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2021] [Accepted: 03/14/2022] [Indexed: 01/07/2023]
Abstract
Confining particles to distances below their de Broglie wavelength discretizes their motional state. This fundamental effect is observed in many physical systems, ranging from electrons confined in atoms or quantum dots1,2 to ultracold atoms trapped in optical tweezers3,4. In solid-state photonics, a long-standing goal has been to achieve fully tunable quantum confinement of optically active electron-hole pairs, known as excitons. To confine excitons, existing approaches mainly rely on material modulation5, which suffers from poor control over the energy and position of trapping potentials. This has severely impeded the engineering of large-scale quantum photonic systems. Here we demonstrate electrically controlled quantum confinement of neutral excitons in 2D semiconductors. By combining gate-defined in-plane electric fields with inherent interactions between excitons and free charges in a lateral p-i-n junction, we achieve exciton confinement below 10 nm. Quantization of excitonic motion manifests in the measured optical response as a ladder of discrete voltage-dependent states below the continuum. Furthermore, we observe that our confining potentials lead to a strong modification of the relative wave function of excitons. Our technique provides an experimental route towards creating scalable arrays of identical single-photon sources and has wide-ranging implications for realizing strongly correlated photonic phases6,7 and on-chip optical quantum information processors8,9.
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Choi J, Hsu WT, Lu LS, Sun L, Cheng HY, Lee MH, Quan J, Tran K, Wang CY, Staab M, Jones K, Taniguchi T, Watanabe K, Chu MW, Gwo S, Kim S, Shih CK, Li X, Chang WH. Moiré potential impedes interlayer exciton diffusion in van der Waals heterostructures. SCIENCE ADVANCES 2020; 6:eaba8866. [PMID: 32967823 PMCID: PMC7531884 DOI: 10.1126/sciadv.aba8866] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 08/06/2020] [Indexed: 05/21/2023]
Abstract
The properties of van der Waals heterostructures are drastically altered by a tunable moiré superlattice arising from periodically varying atomic alignment between the layers. Exciton diffusion represents an important channel of energy transport in transition metal dichalcogenides (TMDs). While early studies performed on TMD heterobilayers suggested that carriers and excitons exhibit long diffusion, a rich variety of scenarios can exist. In a moiré crystal with a large supercell and deep potential, interlayer excitons may be completely localized. As the moiré period reduces at a larger twist angle, excitons can tunnel between supercells and diffuse over a longer lifetime. The diffusion should be the longest in commensurate heterostructures where the moiré superlattice is completely absent. Here, we experimentally demonstrate the rich phenomena of interlayer exciton diffusion in WSe2/MoSe2 heterostructures by comparing several samples prepared with chemical vapor deposition and mechanical stacking with accurately controlled twist angles.
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Affiliation(s)
- Junho Choi
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Wei-Ting Hsu
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Li-Syuan Lu
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Liuyang Sun
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Hui-Yu Cheng
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan
| | - Ming-Hao Lee
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Jiamin Quan
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Kha Tran
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Chun-Yuan Wang
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
- Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Matthew Staab
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Kayleigh Jones
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Takashi Taniguchi
- 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
| | - Ming-Wen Chu
- Center for Condensed Matter Sciences, National Taiwan University, Taipei 10617, Taiwan
| | - Shangjr Gwo
- Department of Physics, National Tsing-Hua University, Hsinchu 30013, Taiwan
- Research Center for Applied Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan
| | - Suenne Kim
- Department of Photonics and Nanoelectronics, Hanyang University, Ansan 15588, Republic of Korea
| | - Chih-Kang Shih
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA
| | - Xiaoqin Li
- Department of Physics, Complex Quantum Systems, and Texas Materials Institute, The University of Texas at Austin, Austin, TX 78712, USA.
| | - Wen-Hao Chang
- Department of Electrophysics, National Chiao Tung University, Hsinchu 30010, Taiwan.
- Center for Emergent Functional Matter Science (CEFMS), National Chiao Tung University, Hsinchu 30010, Taiwan
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5
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Yuan L, Zheng B, Kunstmann J, Brumme T, Kuc AB, Ma C, Deng S, Blach D, Pan A, Huang L. Twist-angle-dependent interlayer exciton diffusion in WS 2-WSe 2 heterobilayers. NATURE MATERIALS 2020; 19:617-623. [PMID: 32393806 DOI: 10.1038/s41563-020-0670-3] [Citation(s) in RCA: 101] [Impact Index Per Article: 25.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2019] [Accepted: 03/25/2020] [Indexed: 05/12/2023]
Abstract
The nanoscale periodic potentials introduced by moiré patterns in semiconducting van der Waals heterostructures have emerged as a platform for designing exciton superlattices. However, our understanding of the motion of excitons in moiré potentials is still limited. Here we investigated interlayer exciton dynamics and transport in WS2-WSe2 heterobilayers in time, space and momentum domains using transient absorption microscopy combined with first-principles calculations. We found that the exciton motion is modulated by twist-angle-dependent moiré potentials around 100 meV and deviates from normal diffusion due to the interplay between the moiré potentials and strong exciton-exciton interactions. Our experimental results verified the theoretical prediction of energetically favourable K-Q interlayer excitons and showed exciton-population dynamics that are controlled by the twist-angle-dependent energy difference between the K-Q and K-K excitons. These results form a basis to investigate exciton and spin transport in van der Waals heterostructures, with implications for the design of quantum communication devices.
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Affiliation(s)
- Long Yuan
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Biyuan Zheng
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Jens Kunstmann
- Theoretical Chemistry, Department of Chemistry and Food Chemistry, TU Dresden, Dresden, Germany
| | - Thomas Brumme
- Wilhelm-Ostwald-Institute for Physical and Theoretical Chemistry, Leipzig University, Leipzig, Germany
| | - Agnieszka Beata Kuc
- Abteilung Ressourcenökologie, Helmholtz-Zentrum Dresden-Rossendorf, Forschungsstelle Leipzig, Leipzig, Germany
- Department of Physics & Earth Science, Jacobs University Bremen, Bremen, Germany
| | - Chao Ma
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Shibin Deng
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Daria Blach
- Department of Chemistry, Purdue University, West Lafayette, IN, USA
| | - Anlian Pan
- Key Laboratory for Micro-Nano Physics and Technology of Hunan Province, State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Materials Science and Engineering, Hunan University, Changsha, People's Republic of China
| | - Libai Huang
- Department of Chemistry, Purdue University, West Lafayette, IN, USA.
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6
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Winbow AG, Leonard JR, Remeika M, Kuznetsova YY, High AA, Hammack AT, Butov LV, Wilkes J, Guenther AA, Ivanov AL, Hanson M, Gossard AC. Electrostatic conveyer for excitons. PHYSICAL REVIEW LETTERS 2011; 106:196806. [PMID: 21668190 DOI: 10.1103/physrevlett.106.196806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Indexed: 05/30/2023]
Abstract
We report on the study of indirect excitons in moving lattices-conveyers created by a set of ac voltages applied to the electrodes on the sample surface. The wavelength of this moving lattice is set by the electrode periodicity, the amplitude is controlled by the applied voltage, and the velocity is controlled by the ac frequency. We found the dynamical localization-delocalization transition for excitons in the conveyers and determined its dependence on exciton density and conveyer amplitude and velocity.
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Affiliation(s)
- A G Winbow
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA
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7
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Völk S, Schülein FJR, Knall F, Reuter D, Wieck AD, Truong TA, Kim H, Petroff PM, Wixforth A, Krenner HJ. Enhanced sequential carrier capture into individual quantum dots and quantum posts controlled by surface acoustic waves. NANO LETTERS 2010; 10:3399-3407. [PMID: 20722408 DOI: 10.1021/nl1013053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Individual self-assembled quantum dots and quantum posts are studied under the influence of a surface acoustic wave. In optical experiments we observe an acoustically induced switching of the occupancy of the nanostructures along with an overall increase of the emission intensity. For quantum posts, switching occurs continuously from predominantly charged excitons (dissimilar number of electrons and holes) to neutral excitons (same number of electrons and holes) and is independent of whether the surface acoustic wave amplitude is increased or decreased. For quantum dots, switching is nonmonotonic and shows a pronounced hysteresis on the amplitude sweep direction. Moreover, emission of positively charged and neutral excitons is observed at high surface acoustic wave amplitudes. These findings are explained by carrier trapping and localization in the thin and disordered two-dimensional wetting layer on top of which quantum dots nucleate. This limitation can be overcome for quantum posts where acoustically induced charge transport is highly efficient in a wide lateral matrix-quantum well.
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Affiliation(s)
- Stefan Völk
- Lehrstuhl für Experimentalphysik 1, Universität Augsburg, Universitätsstrasse 1, 86159 Augsburg, Germany
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