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Extended Bose–Hubbard model with dipolar excitons. Nature 2022; 609:485-489. [DOI: 10.1038/s41586-022-05123-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Accepted: 07/19/2022] [Indexed: 11/08/2022]
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2
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Shanks DN, Mahdikhanysarvejahany F, Stanfill TG, Koehler MR, Mandrus DG, Taniguchi T, Watanabe K, LeRoy BJ, Schaibley JR. Interlayer Exciton Diode and Transistor. NANO LETTERS 2022; 22:6599-6605. [PMID: 35969812 DOI: 10.1021/acs.nanolett.2c01905] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Controlling the flow of charge neutral interlayer exciton (IX) quasiparticles can potentially lead to low loss excitonic circuits. Here, we report unidirectional transport of IXs along nanoscale electrostatically defined channels in an MoSe2-WSe2 heterostructure. These results are enabled by a lithographically defined triangular etch in a graphene gate to create a potential energy "slide". By performing spatially and temporally resolved photoluminescence measurements, we measure smoothly varying IX energy along the structure and high speed exciton flow with a drift velocity up to 2 × 106 cm/s, an order of magnitude larger than previous experiments. Furthermore, exciton flow can be controlled by saturating exciton population in the channel using a second laser pulse, demonstrating an optically gated excitonic transistor. Our work paves the way toward low loss excitonic circuits, the study of bosonic transport in one-dimensional channels, and custom potential energy landscapes for excitons in van der Waals heterostructures.
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Affiliation(s)
- Daniel N Shanks
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | | | - Trevor G Stanfill
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | - Michael R Koehler
- IAMM Diffraction Facility, Institute for Advanced Materials and Manufacturing, University of Tennessee, Knoxville, Tennessee 37920, United States
| | - David G Mandrus
- Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996, United States
- Materials Science and Technology Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
- Department of Physics and Astronomy, University of Tennessee, Knoxville, Tennessee 37996, United States
| | - Takashi Taniguchi
- International Center for Materials Nanoarchitectonics, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Kenji Watanabe
- Research Center for Functional Materials, National Institute for Materials Science, 1-1 Namiki, Tsukuba 305-0044, Japan
| | - Brian J LeRoy
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
| | - John R Schaibley
- Department of Physics, University of Arizona, Tucson, Arizona 85721, United States
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Lagoin C, Suffit S, West K, Baldwin K, Pfeiffer L, Holzmann M, Dubin F. Quasicondensation of Bilayer Excitons in a Periodic Potential. PHYSICAL REVIEW LETTERS 2021; 126:067404. [PMID: 33635707 DOI: 10.1103/physrevlett.126.067404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2020] [Accepted: 01/14/2021] [Indexed: 06/12/2023]
Abstract
We study two-dimensional excitons confined in a lattice potential, for high fillings of the lattice sites. We show that a quasicondensate is possibly formed for small values of the lattice depth, but for larger ones the critical phase-space density for quasicondensation rapidly exceeds our experimental reach, due to an increase of the exciton effective mass. On the other hand, in the regime of a deep lattice potential where excitons are strongly localized at the lattice sites, we show that an array of phase-independent quasicondensates, different from a Mott insulator, is realized.
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Affiliation(s)
- Camille Lagoin
- Institut des Nanosciences de Paris, CNRS and Sorbonne Université, 4 pl. Jussieu, 75005 Paris, France
| | - Stephan Suffit
- Laboratoire de Materiaux et Phenomenes Quantiques, Universite Paris Diderot, 75013 Paris, France
| | - Kenneth West
- PRISM, Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, USA
| | - Kirk Baldwin
- PRISM, Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, USA
| | - Loren Pfeiffer
- PRISM, Princeton Institute for the Science and Technology of Materials, Princeton University, Princeton, New Jersey 08540, USA
| | | | - François Dubin
- Institut des Nanosciences de Paris, CNRS and Sorbonne Université, 4 pl. Jussieu, 75005 Paris, France
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Calman EV, Fowler-Gerace LH, Choksy DJ, Butov LV, Nikonov DE, Young IA, Hu S, Mishchenko A, Geim AK. Indirect Excitons and Trions in MoSe 2/WSe 2 van der Waals Heterostructures. NANO LETTERS 2020; 20:1869-1875. [PMID: 32069058 DOI: 10.1021/acs.nanolett.9b05086] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Indirect excitons (IX) in semiconductor heterostructures are bosons, which can cool below the temperature of quantum degeneracy and can be effectively controlled by voltage and light. IX quantum Bose gases and IX devices were explored in GaAs heterostructures where an IX range of existence is limited to low temperatures due to low IX binding energies. IXs in van der Waals transition-metal dichalcogenide (TMD) heterostructures are characterized by large binding energies giving the opportunity for exploring excitonic quantum gases and for creating excitonic devices at high temperatures. TMD heterostructures also offer a new platform for studying single-exciton phenomena and few-particle complexes. In this work, we present studies of IXs in MoSe2/WSe2 heterostructures and report on two IX luminescence lines whose energy splitting and temperature dependence identify them as neutral and charged IXs. The experimentally found binding energy of the indirect charged excitons, that is, indirect trions, is close to the calculated binding energy of 28 meV for negative indirect trions in TMD heterostructures [Deilmann, T.; Thygesen, K. S. Nano Lett. 2018, 18, 1460]. We also report on the realization of IXs with a luminescence line width reaching 4 meV at low temperatures. An enhancement of IX luminescence intensity and the narrow line width are observed in localized spots.
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Affiliation(s)
- E V Calman
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - L H Fowler-Gerace
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - D J Choksy
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - L V Butov
- Department of Physics, University of California at San Diego, La Jolla, California 92093, United States
| | - D E Nikonov
- Components Research, Intel Corporation, Hillsboro, Oregon 97124 United States
| | - I A Young
- Components Research, Intel Corporation, Hillsboro, Oregon 97124 United States
| | - S Hu
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - A Mishchenko
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
| | - A K Geim
- School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL, United Kingdom
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Shiau SY, Combescot M. Optical Signature of Quantum Coherence in Fully Dark Exciton Condensates. PHYSICAL REVIEW LETTERS 2019; 123:097401. [PMID: 31524492 DOI: 10.1103/physrevlett.123.097401] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/18/2019] [Indexed: 06/10/2023]
Abstract
We predict that the collision of two fully dark exciton condensates produces bright interference fringes. So, quite surprisingly, the collision of coherent dark states makes light. This remarkable effect, which is many body in essence, comes from the composite boson nature of excitons, through the fermion exchanges they can have which transform dark states into bright states. The possibility of optically detecting quantum coherence in a regime where the system is hidden by its total darkness was up to now considered as hopeless.
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Affiliation(s)
- Shiue-Yuan Shiau
- Physics Division, National Center for Theoretical Sciences, Hsinchu, 30013, Taiwan
| | - Monique Combescot
- Sorbonne Université, CNRS, Institut des NanoSciences de Paris, 75005-Paris, France
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Togan E, Lim HT, Faelt S, Wegscheider W, Imamoglu A. Enhanced Interactions between Dipolar Polaritons. PHYSICAL REVIEW LETTERS 2018; 121:227402. [PMID: 30547610 DOI: 10.1103/physrevlett.121.227402] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Revised: 10/16/2018] [Indexed: 06/09/2023]
Abstract
Nonperturbative coupling between cavity photons and excitons leads to the formation of hybrid light-matter excitations, termed polaritons. In structures where photon absorption leads to the creation of excitons with aligned permanent dipoles, the elementary excitations, termed dipolar polaritons, are expected to exhibit enhanced interactions. Here, we report a substantial increase in interaction strength between dipolar polaritons as the size of the dipole is increased by tuning the applied gate voltage. To this end, we use coupled quantum well structures embedded inside a microcavity where coherent electron tunneling between the wells creates the excitonic dipole. Modifications of the interaction strength are characterized by measuring the changes in the reflected light intensity when polaritons are driven with a resonant laser. The factor of 6.5 increase in the interaction-strength-to-linewidth ratio that we obtain indicates that dipolar polaritons could constitute an important step towards a demonstration of the polariton blockade effect, and thereby to form the building blocks of many-body states of light.
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Affiliation(s)
- Emre Togan
- Institute of Quantum Electronics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Hyang-Tag Lim
- Institute of Quantum Electronics, ETH Zurich, CH-8093 Zurich, Switzerland
| | - Stefan Faelt
- Institute of Quantum Electronics, ETH Zurich, CH-8093 Zurich, Switzerland
- Solid State Physics Laboratory, ETH Zurich, CH-8093 Zurich, Switzerland
| | | | - Atac Imamoglu
- Institute of Quantum Electronics, ETH Zurich, CH-8093 Zurich, Switzerland
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Sivalertporn K, Muljarov EA. Controlled Strong Coupling and Absence of Dark Polaritons in Microcavities with Double Quantum Wells. PHYSICAL REVIEW LETTERS 2015; 115:077401. [PMID: 26317745 DOI: 10.1103/physrevlett.115.077401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Indexed: 06/04/2023]
Abstract
We demonstrate an efficient switching between strong and weak exciton-photon coupling regimes in microcavity-embedded asymmetric double quantum wells, controlled by an applied electric field. We show that a fine-tuning of the electric field leads to drastic changes in the polariton properties, with the polariton ground state being redshifted by a few meV and having acquired prominent features of a spatially indirect dipolar exciton. We study the properties of dipolar exciton polaritons, called dipolaritons, on a microscopic level and show that, unlike recent findings, they are not dark polaritons but, owing to the finite size of the exciton, are mixed states with a comparable contribution of the cavity photon, bright direct, and long-living indirect exciton modes.
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Affiliation(s)
- K Sivalertporn
- Department of Physics, Faculty of Science, Ubon Ratchathani University, Ubon Ratchathani 34190, Thailand
| | - E A Muljarov
- School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA, United Kingdom
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Grasselli F, Bertoni A, Goldoni G. Space- and time-dependent quantum dynamics of spatially indirect excitons in semiconductor heterostructures. J Chem Phys 2015; 142:034701. [PMID: 25612719 DOI: 10.1063/1.4905483] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We study the unitary propagation of a two-particle one-dimensional Schrödinger equation by means of the Split-Step Fourier method, to study the coherent evolution of a spatially indirect exciton (IX) in semiconductor heterostructures. The mutual Coulomb interaction of the electron-hole pair and the electrostatic potentials generated by external gates and acting on the two particles separately are taken into account exactly in the two-particle dynamics. As relevant examples, step/downhill and barrier/well potential profiles are considered. The space- and time-dependent evolutions during the scattering event as well as the asymptotic time behavior are analyzed. For typical parameters of GaAs-based devices, the transmission or reflection of the pair turns out to be a complex two-particle process, due to comparable and competing Coulomb, electrostatic, and kinetic energy scales. Depending on the intensity and anisotropy of the scattering potentials, the quantum evolution may result in excitation of the IX internal degrees of freedom, dissociation of the pair, or transmission in small periodic IX wavepackets due to dwelling of one particle in the barrier region. We discuss the occurrence of each process in the full parameter space of the scattering potentials and the relevance of our results for current excitronic technologies.
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Affiliation(s)
- Federico Grasselli
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena, Italy
| | - Andrea Bertoni
- CNR-NANO S3, Institute for Nanoscience, Via Campi 213/a, 41125 Modena, Italy
| | - Guido Goldoni
- Department of Physics, Informatics and Mathematics, University of Modena and Reggio Emilia, Modena, Italy
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Alloing M, Lemaître A, Galopin E, Dubin F. Optically programmable excitonic traps. Sci Rep 2013; 3:1578. [PMID: 23546532 PMCID: PMC3613794 DOI: 10.1038/srep01578] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2012] [Accepted: 03/13/2013] [Indexed: 11/23/2022] Open
Abstract
With atomic systems, optically programmed trapping potentials have led to remarkable progress in quantum optics and quantum information science. Programmable trapping potentials could have a similar impact on studies of semiconductor quasi-particles, particularly excitons. However, engineering such potentials inside a semiconductor heterostructure remains an outstanding challenge and optical techniques have not yet achieved a high degree of control. Here, we synthesize optically programmable trapping potentials for indirect excitons of bilayer heterostructures. Our approach relies on the injection and spatial patterning of charges trapped in a field-effect device. We thereby imprint in-situ and on-demand electrostatic traps into which we optically inject cold and dense ensembles of excitons. This technique creates new opportunities to improve state-of-the-art technologies for the study of collective quantum behavior of excitons and also for the functionalisation of emerging exciton-based opto-electronic circuits.
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Affiliation(s)
- Mathieu Alloing
- ICFO-The Institute of Photonic Sciences, Av. Carl Friedrich Gauss, num. 3, 08860 Castelldefels (Barcelona), Spain
| | - Aristide Lemaître
- Laboratoire de Photonique et Nanostructures, CNRS, Route de Nozay, 91460 Marcoussis, France
| | - Elisabeth Galopin
- Laboratoire de Photonique et Nanostructures, CNRS, Route de Nozay, 91460 Marcoussis, France
| | - François Dubin
- ICFO-The Institute of Photonic Sciences, Av. Carl Friedrich Gauss, num. 3, 08860 Castelldefels (Barcelona), Spain
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