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Collective interlayer pairing and pair superfluidity in vertically stacked layers of dipolar excitons. Proc Natl Acad Sci U S A 2022; 119:e2205845119. [PMID: 35858431 PMCID: PMC9335227 DOI: 10.1073/pnas.2205845119] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Layered bosonic dipolar fluids have been suggested to host a condensate of interlayer molecular bound states. However, experimental observation has remained elusive. Motivated by two recent experimental works [C. Hubert et al., Phys. Rev. X9, 021026 (2019) and D. J. Choksy et al., Phys. Rev. B 103, 045126 (2021)], we theoretically study, using numerically exact quantum Monte Carlo calculations, the experimental signatures of collective interlayer pairing in vertically stacked indirect exciton (IX) layers. We find that IX energy shifts associated with each layer evolve nontrivially as a function of density imbalance following a nonmonotonic trend with a jump discontinuity at density balance, identified with the interlayer IX molecule gap. This behavior discriminates between the superfluidity of interlayer bound pairs and independent dipole condensation in distinct layers. Considering finite temperature and finite density imbalance conditions, we find a cascade of Berezinskii-Kosterlitz-Thouless (BKT) transitions, initially into a pair superfluid and only then, at lower temperatures, into complete superfluidity of both layers. Our results may provide a theoretical interpretation of existing experimental observations in GaAs double quantum well (DQW) bilayer structures. Furthermore, to optimize the visibility of pairing dynamics in future studies, we present an analysis suggesting realistic experimental settings in GaAs and transition metal dichalcogenide (TMD) bilayer DQW heterostructures where collective interlayer pairing and pair superfluidity can be clearly observed.
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Sugakov VI. Exciton condensation in quantum wells with defects of macroscopic sizes. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2019; 31:475301. [PMID: 31429421 DOI: 10.1088/1361-648x/ab36ec] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Formation of the excitonic condensed phase in quantum wells with defects of macroscopic size is investigated in the case of a specific kind of defect arising in local areas of planar quantum wells where the wells are thicker or thinner by an atomic monolayer or two. The excitonic system in the wells is non-equilibrium as the excitons are constantly created by an irradiation and decay due to the finite lifetime. The condensation considered in the paper is not the Bose-Einstein condensation but rather the classical condensation due an interaction between excitons with additional peculiarities caused by non-equilibrium conditions. The main contribution to the exciton's energy in the defect's area comes from the energy of the exciton's confinement along the growth axis and the respective quantization of the exciton's levels. The condensation manifests itself by an enhancement the exciton accumulation in the defect's area with increasing pumping and by an appearance of different types of structures in the exciton density distribution when the defect's size is large. The condensed phase may appear in the form of islands or in the form of rings on the defect's boundary. It is shown, that the value of the exciton's lifetime plays an important role in the spatial distribution of the exciton density. The similarity and the difference of density structures for wells with the extra or lacking atomic monolayer in the defect's area are investigated. The specific features of the manifestation of the exciton luminescence at the condensation in the defect's region is analyzed.
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Affiliation(s)
- V I Sugakov
- Institute for Nuclear Research, National Academy of Sciences of Ukraine, 47, Nauki Ave., Kyiv 03680, Ukraine
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Chiaruttini F, Guillet T, Brimont C, Jouault B, Lefebvre P, Vives J, Chenot S, Cordier Y, Damilano B, Vladimirova M. Trapping Dipolar Exciton Fluids in GaN/(AlGa)N Nanostructures. NANO LETTERS 2019; 19:4911-4918. [PMID: 31241962 DOI: 10.1021/acs.nanolett.9b00914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Dipolar excitons offer a rich playground for both design of novel optoelectronic devices and fundamental many-body physics. Wide GaN/(AlGa)N quantum wells host a new and promising realization of dipolar excitons. We demonstrate the in-plane confinement and cooling of these excitons, when trapped in the electrostatic potential created by semitransparent electrodes of various shapes deposited on the sample surface. This result is a prerequisite for the electrical control of the exciton densities and fluxes, as well for studies of the complex phase diagram of these dipolar bosons at low temperature.
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Affiliation(s)
- François Chiaruttini
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
| | - Thierry Guillet
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
| | - Christelle Brimont
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
| | - Benoit Jouault
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
| | - Pierre Lefebvre
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
| | - Jessica Vives
- CRHEA , Université Côte d'Azur, CNRS, Rue Bernard Gregory , F-06560 , Valbonne , France
| | - Sebastien Chenot
- CRHEA , Université Côte d'Azur, CNRS, Rue Bernard Gregory , F-06560 , Valbonne , France
| | - Yvon Cordier
- CRHEA , Université Côte d'Azur, CNRS, Rue Bernard Gregory , F-06560 , Valbonne , France
| | - Benjamin Damilano
- CRHEA , Université Côte d'Azur, CNRS, Rue Bernard Gregory , F-06560 , Valbonne , France
| | - Maria Vladimirova
- L2C , Université de Montpellier, CNRS, Place Eugène Bataillon , F-34095 , Montpellier , France
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Combescot M, Combescot R, Dubin F. Bose-Einstein condensation and indirect excitons: a review. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2017; 80:066501. [PMID: 28355164 DOI: 10.1088/1361-6633/aa50e3] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We review recent progress on Bose-Einstein condensation (BEC) of semiconductor excitons. The first part deals with theory, the second part with experiments. This Review is written at a time where the problem of exciton Bose-Einstein condensation has just been revived by the understanding that the exciton condensate must be dark because the exciton ground state is not coupled to light. Here, we theoretically discuss this missed understanding before providing its experimental support through experiments that scrutinize indirect excitons made of spatially separated electrons and holes. The theoretical part first discusses condensation of elementary bosons. In particular, the necessary inhibition of condensate fragmentation by exchange interaction is stressed, before extending the discussion to interacting bosons with spin degrees of freedom. The theoretical part then considers composite bosons made of two fermions like semiconductor excitons. The spin structure of the excitons is detailed, with emphasis on the crucial fact that ground-state excitons are dark: indeed, this imposes the exciton Bose-Einstein condensate to be not coupled to light in the dilute regime. Condensate fragmentations are then reconsidered. In particular, it is shown that while at low density, the exciton condensate is fully dark, it acquires a bright component, coherent with the dark one, beyond a density threshold: in this regime, the exciton condensate is 'gray'. The experimental part first discusses optical creation of indirect excitons in quantum wells, and the detection of their photoluminescence. Exciton thermalisation is also addressed, as well as available approaches to estimate the exciton density. We then switch to specific experiments where indirect excitons form a macroscopic fragmented ring. We show that such ring provides efficient electrostatic trapping in the region of the fragments where an essentially-dark exciton Bose-Einstein condensate is formed at sub-Kelvin bath temperatures. The macroscopic spatial coherence of the photoluminescence observed in this essentially dark region confirms this conclusion.
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Affiliation(s)
- Monique Combescot
- Institut des NanoSciences de Paris, Université Pierre et Marie Curie, CNRS, Tour 22, 4 place Jussieu, 75005 Paris, France
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Anankine R, Beian M, Dang S, Alloing M, Cambril E, Merghem K, Carbonell CG, Lemaître A, Dubin F. Quantized Vortices and Four-Component Superfluidity of Semiconductor Excitons. PHYSICAL REVIEW LETTERS 2017; 118:127402. [PMID: 28388190 DOI: 10.1103/physrevlett.118.127402] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Indexed: 06/07/2023]
Abstract
We study spatially indirect excitons of GaAs quantum wells, confined in a 10 μm electrostatic trap. Below a critical temperature of about 1 K, we detect macroscopic spatial coherence and quantized vortices in the weak photoluminescence emitted from the trap. These quantum signatures are restricted to a narrow range of density, in a dilute regime. They manifest the formation of a four-component superfluid, made by a low population of optically bright excitons coherently coupled to a dominant fraction of optically dark excitons.
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Affiliation(s)
- Romain Anankine
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 Place Jussieu, F-75005 Paris, France
| | - Mussie Beian
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 Place Jussieu, F-75005 Paris, France
- ICFO-The Institute of Photonic Sciences, Av. Carl Friedrich Gauss, num. 3, 08860 Castelldefels, Spain
| | - Suzanne Dang
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 Place Jussieu, F-75005 Paris, France
| | - Mathieu Alloing
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 Place Jussieu, F-75005 Paris, France
| | - Edmond Cambril
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
| | - Kamel Merghem
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
| | - Carmen Gomez Carbonell
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
| | - Aristide Lemaître
- Laboratoire de Photonique et Nanostructures, LPN/CNRS, Route de Nozay, 91460 Marcoussis, France
| | - François Dubin
- Sorbonne Universités, UPMC Univ. Paris 06, CNRS-UMR 7588, Institut des NanoSciences de Paris, 4 Place Jussieu, F-75005 Paris, France
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Kuznetsova YY, Andreakou P, Hasling MW, Leonard JR, Calman EV, Butov LV, Hanson M, Gossard AC. Two-dimensional snowflake trap for indirect excitons. OPTICS LETTERS 2015; 40:589-592. [PMID: 25680157 DOI: 10.1364/ol.40.000589] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
We present experimental proof of principle for two-dimensional electrostatic traps for indirect excitons. A confining trap potential for indirect excitons is created by a snowflake-shaped electrode pattern. We demonstrate collection of indirect excitons from all directions to the trap center and control of the trap potential by voltage.
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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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Xu TF, Jing XL, Luo HG, Wu WC, Liu CS. Interplay between periodicity and nonlinearity of indirect excitons in coupled quantum wells. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:455301. [PMID: 23072970 DOI: 10.1088/0953-8984/24/45/455301] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Inspired by a recent experiment of localization-delocalization transition (LDT) of indirect excitons in lateral electrostatic lattices (Remeika et al 2009 Phys. Rev. Lett. 102 186803), we theoretically investigate the interplay between periodic potential and nonlinear interactions of indirect excitons in coupled quantum wells. It is shown that the model involving both attractive two-body and repulsive three-body interactions can lead to a natural account for the LDT of excitons across the lattice when reducing lattice amplitude or increasing particle density. In addition, the observations that the smooth component of the photoluminescent energy increases with increasing exciton density and that the exciton interaction energy is close to the lattice amplitude at the transition are also qualitatively explained. Our model provides an alternative way of understanding the underlying physics of the exciton dynamics in lattice potential wells.
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Affiliation(s)
- T F Xu
- Department of Physics, Yanshan University, Qinhuangdao 066004, People's Republic of China
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High AA, Leonard JR, Remeika M, Butov LV, Hanson M, Gossard AC. Condensation of excitons in a trap. NANO LETTERS 2012; 12:2605-2609. [PMID: 22509898 DOI: 10.1021/nl300983n] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Condensation is observed in a gas of indirect excitons confined in an electrostatic trap. Imaging and interferometric measurements detect that excitons condense at the trap bottom and exciton spontaneous coherence emerges with lowering temperature. Below a temperature of about 1 K, the direct signature of Bose-Einstein condensation, the extension of coherence over the entire cloud, is observed.
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Affiliation(s)
- A A High
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA.
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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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Cerda-Méndez EA, Krizhanovskii DN, Wouters M, Bradley R, Biermann K, Guda K, Hey R, Santos PV, Sarkar D, Skolnick MS. Polariton condensation in dynamic acoustic lattices. PHYSICAL REVIEW LETTERS 2010; 105:116402. [PMID: 20867591 DOI: 10.1103/physrevlett.105.116402] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2010] [Revised: 08/06/2010] [Indexed: 05/29/2023]
Abstract
We demonstrate that the tunable potential introduced by a surface acoustic wave on a homogeneous polariton condensate leads to fragmentation of the condensate into an array of wires which move with the acoustic velocity. Reduction of the spatial coherence of the condensate emission along the surface acoustic wave direction is attributed to the suppression of coupling between the spatially modulated condensates. Interparticle interactions observed at high polariton densities screen the acoustic potential, partially reversing its effect on spatial coherence.
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Leonard JR, Kuznetsova YY, Yang S, Butov LV, Ostatnický T, Kavokin A, Gossard AC. Spin transport of excitons. NANO LETTERS 2009; 9:4204-4208. [PMID: 19780583 DOI: 10.1021/nl9024227] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
We report on observation of the spin transport of spatially indirect excitons in GaAs/AlGaAs coupled quantum wells (CQW). Exciton spin transport over substantial distances, up to several micrometers in the present work, is achieved due to orders of magnitude enhancement of the exciton spin relaxation time in CQW with respect to conventional quantum wells.
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Affiliation(s)
- J R Leonard
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA.
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High AA, Thomas AK, Grosso G, Remeika M, Hammack AT, Meyertholen AD, Fogler MM, Butov LV, Hanson M, Gossard AC. Trapping indirect excitons in a GaAs quantum-well structure with a diamond-shaped electrostatic trap. PHYSICAL REVIEW LETTERS 2009; 103:087403. [PMID: 19792761 DOI: 10.1103/physrevlett.103.087403] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Indexed: 05/28/2023]
Abstract
We report on the principle and realization of a new trap for excitons--the diamond electrostatic trap--which uses a single electrode to create a confining potential for excitons. We also create elevated diamond traps which permit evaporative cooling of the exciton gas. We observe the collection of excitons towards the trap center with increasing exciton density. This effect is due to screening of disorder in the trap by the excitons. As a result, the diamond trap behaves as a smooth parabolic potential which realizes a cold and dense exciton gas at the trap center.
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Affiliation(s)
- A A High
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA
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High AA, Hammack AT, Butov LV, Mouchliadis L, Ivanov AL, Hanson M, Gossard AC. Indirect excitons in elevated traps. NANO LETTERS 2009; 9:2094-2098. [PMID: 19382780 DOI: 10.1021/nl900605b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We report on the study of indirect excitons in elevated traps. The transition from a normal to elevated trap results in the appearance of narrow lines in the emission spectrum. The density, temperature, and voltage dependences indicate that these lines correspond to the emission of individual states of indirect excitons in a disorder potential in the elevated trap.
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Affiliation(s)
- A A High
- Department of Physics, University of California at San Diego, La Jolla, California 92093-0319, USA.
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