Search query: Excitons bound by photon exchange

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abstract: In contrast to interband excitons in undoped quantum wells, doped quantum wells do not display sharp resonances due to excitonic bound states. The effective Coulomb interaction between electrons and holes in these systems typically leads to only a depolarization shift of the single electron intersubband transitions 1 Non perturbative light matter interaction in solid state devices has been investigated as a pathway to tuning optoelectronic properties of materials 2 3 A recent theoretical work 4 predicted that when the doped quantum wells are embedded in a photonic cavity, emission reabsorption processes of cavity photons can generate an effective attractive interaction that binds electrons and holes together, leading to the creation of an intraband bound exciton. Here, we spectroscopically observe such a bound state as a discrete resonance that appears below the ionization threshold only when the coupling between light and matter is increased above a critical value. Our result demonstrates that two charged particles can be bound by the exchange of transverse photons. Light matter coupling can thus be used as a tool in quantum material engineering, tuning electronic properties of semiconductor heterostructures beyond those permitted by mere crystal structures, with direct applications to mid infrared optoelectronics. Electrons and holes in doped quantum wells cannot form bound states from usual Coulomb interaction. However, when the system is embedded in a cavity, the exchange of photons provides an effective attraction, leading to the creation of bound excitons.
author_names: Erika Cortese

N L Tran

J-M Manceau

Adel Bousseksou

Iacopo Carusotto

Giorgio Biasiol

Raffaele Colombelli

Simone De Liberato
title: Excitons bound by photon exchange
year: 2019

abstract: In semimagnetic semiconductors, magnetic polaron bound to donors and acceptors have been well studied [1] and are now well understood theoretic cally [2 4] Despite the fact that magnetic polaron shift in the luminescence of bound excitons were studied since 1980 [5 6] many aspects are still to be explained. In this paper, we use the best available wavefunc tions of exciton complexes [7 8] We compute the contribution of exchange between the magnetic ions and the bound particles as a perturbation. The process involving the impurity Ideg, the exciton X and the photon hvis: X Ideg IdegX hv+ IdegAt the time of photon emission, we can admit safely that a strong dipolar allowed process occurs with conservation of the magnetization. But since the lifetime of the excited state is known to be about 1 nsec, we have to wonder if the magnetic moments have time to adjust to the electronic exci ted state. Calculations are done in the two limits: a) Slow orientation of the moments. The magnetization map M(r) at the time of luminescence is fixed by thermalization in the ground state Ideg. b) Fast orientation of th moments. M(r) is fixed by thermalization in the IdegX state.
author_names: R Planel

J Cernogora

Jan A Gaj

Christophe L Guillaume
title: Magnetic Polaron Effects on Bound Excitons
year: 1985

abstract: Within the framework of ab initio Time Dependent Density Functional Theory (TD DFT) we propose a static approximation to the exchange correlation kernel based on the jellium with gap model. This kernel accounts for electron hole interactions and it is able to address both strongly bound excitons and weak excitonic effects. TD DFT absorption spectra of several bulk materials (both semiconductor and insulators) are reproduced in very good agreement with the experiments and with a low computational cost. The theoretical description of the optical properties of materials by first principles calculations is one of the classical issues in solid state physics. After photon absorption, the excitonic effects, driven by the electron and hole (e h) interactions, are principal actors, rendering the ab initio computational description demanding. The most successful approach is, so far, based on ManyBody Perturbation theory: the GW self energy accounts for electron electron (e e) many body effects in the band structure calculations, whereas the Bethe Salpeter Equation is solved to introduce e h interactions [1] This accu
author_names: Paolo E Trevisanutto

Aleksandrs Terentjevs

Lucian A Constantin

V Olevano

Fabio Della Sala
title: Optical Spectra of Solids Obtained by Time Dependent Density Functional Theory with the Jellium with Gap Model Exchange Correlation Kernel
year: 2013

abstract: Quantum communication networks require on chip transfer and manipulation of single particles as well as their interconversion to single photons for long range information exchange. Flying excitons propelled by GHz surface acoustic waves (SAWs) are outstanding messengers to fulfill these requirements. Here, we demonstrate the acoustic manipulation of two level states consisting of individual excitons bound to shallow impurities centers embedded in a semiconductor quantum well. Time resolved photoluminescence studies show that the emission intensity and energy from these centers oscillate at the SAW frequency of 3.5 GHz. Furthermore, these centers can be remotely pumped via acoustic transport along a quantum well channel over several micron. Time correlation studies reveal that the centers emit anti bunched light, thus acting as single photon sources operating at GHz frequencies. Our results pave the way for the exciton based on demand manipulation and on chip transfer of single excitons at microwave frequencies with a natural photonic interface.
author_names: M Yuan

Klaus Biermann

Shin-ya Takada

C Bauerle

Paulo Ventura Santos
title: Remotely pumped GHz anti bunched emission from single exciton states
year: 2020

abstract: In cavity quantum electrodynamics, strong light matter coupling is normally observed between a photon mode and a discrete optically active transition. In the present work we demonstrate that strong coupling can also be achieved using ionizing, intrinsically continuum, transitions. This leads to the appearance of novel discrete polaritonic resonances, corresponding to dressed bound exciton states, kept together by the exchange of virtual cavity photons. We apply our theory to the case of intersubband transitions in doped quantum wells, where Coulomb bound excitons are absent. In considering quantum wells with a single bound electronic subband, in which all transitions involve states in the continuum, we find that the novel bound excitons predicted by our theory are observable within present day, realistic parameters. Our work shows how strong light matter coupling can be used as a novel gauge to tune both optical and electronic properties of semiconductor heterostructures beyond those permitted by mere crystal properties.
author_names: Erika Cortese

Iacopo Carusotto

Raffaele Colombelli

Simone De Liberato
title: Strong coupling of ionizing transitions
venue: Optica
year: 2019

abstract: Oxygen substituting for Te in ZnTe is an isoelectronic impurity that traps excitons. The recombination radiation and absorption spectra attributed to isolated oxygen centers exhibit a no phonon line accompanied by emission of multiple phonons. The two resulting spectra are `mirror images' of each other in energy with respect to that of the no phonon line. Photoluminescence and absorption measurements on specimens with significantly higher oxygen concentration disclosed additional spectral features with four no phonon lines, all displaced to lower energies with respect to that of isolated oxygen. Photoluminescence spectra of the present no phonon lines show a temperature dependence characteristic of exchange coupling between an electron and a hole. Selective excitation with photon energies less than that of the no phonon line of isolated oxygen permitted a clear observation of the features free from the phonon sidebands of isolated oxygen. These features, including phonon replicas, appear to be due to excitons bound to oxygen pairs, with different OO separations.
author_names: Maeng-Je Seong

Ireneusz Miotkowski

Anant K Ramdas
title: OXYGEN ISOELECTRONIC IMPURITIES IN ZNTE: PHOTOLUMINESCENCE AND ABSORPTION SPECTROSCOPY
year: 1998

abstract: SummaryThe existence of the excitonic molecule as bound state of Wannier excitons was predicted since 1958. In recent years new lines were observed in the luminescence spectra of crystals excited by high power lasers. These lines were attributed to the dissociation of the molecule into a free exciton and a photon. We establish the classification of the biexcitonic states taking into account the details of the band structure and the symmetry properties of the crystals. Different numerical calculations of the binding energy of the molecule are presented, some including electron hole exchange corrections. Discrepancies still exist between different authors. According to the group theoretical classification of the biexciton states, selection rules of luminescence and two photon absorption are derived. For two photon absorption, besides the usual selection rules for dipole transitions, dynamical selection rules were evidenced.RiassuntoFin dal 1958 si e predetta l'esistenza della molecola eccitonica come stato legato degli eccitoni di Wannier. Negli anni recenti si sono osservate nuove righe negli spettri di luminescenza di cristalli eccitati da laser di alta potenza. Queste linee sono state attribuite alla dissociazione della molecola in un eccitone libero e in un fotone. Si stabilisce la classificazione degli stati bieccitonici prendendo in considerazione i dettagli della struttura a bande e le proprieta di simmetria dei cristalli. Si presentano diversi calcoli numerici dell'energia di legame delle molecole, alcuni comprendenti correzioni dovute allo scambio elettrone buca. Esistono ancora discrepanze tra i diversi autori. Si derivano, seguendo la classificazione degli stati bieccitonici secondo la teoria dei gruppi, le regole di selezione della luminescenza e dell'assorbimento a due fotoni. Per l'assorbimento a due fotoni sono state messe in evidenza, accanto alle usuali regole di selezione per le transizioni dipolari, regole di selezione dinamiche.ReziumeSushchestvovanie eksitonnoi molekuly, kak sviazannogo sostoianiia eksitonov vann'e, bylo predskazano v 1958. V poslednie gody nabliudalis' novye linii v spektrakh liuminestsentsii kristallov, vozbuzhdaemykh lazerami s vysokoi intensivnost'iu. Eti linii pripisyvaiutsia dissotsiatsii molekuly na svobodnyi eksiton i foton. My ustanavlivaem klassifikatsiiu bieksitonnykh sostoianii, prinimaia vo vnimanie detali zonnoi struktury i svoistva simmetrii kristallov. Predlagaiutsia razlichnye vychisleniia energii sviazi molekuly, kotorye vkliuchaiut elektron dyrochnye obmennye popravki. Otmechaiutsia raskhozhdeniia mezhdu dannymi raznykh avtorov. V sootvetstvii s klassifikatsiei teorii grupp dlia bieksitonnykh sostoianii, vyvodiatsia pravila otbora dlia liuminestsentsii i dvukhfotonnogo pogloshcheniia. Dlia dvukhfotonnogo pogloshcheniia, krome obychnykh pravil otbora dlia dipol'nykh perekhodov, podtverzhdaiutsia dinamicheskie pravila otbora.
author_names: Antonio Quattropani

J J Forney
title: Theory of excitonic molecules
year: 1977

abstract: The inelastic collision of two excitons or the optical decay of a biexciton can induce a transition into an exciton and a photon. From the symmetry point of view, we have studied the states of free and bound biexcitons in bulk GaN with the wurtzite structure and in GaN/AlN heterostructures. Due to the antisymmetry properties arising from the exchange of identical fermions, the ground state of the free G biexcitons involving two holes from the same valence band is totally symmetric with respect to the symmetry group of the structure. We established the optical selection rules as well as the possible channels for the processes mentioned above and showed that, whatever is the symmetry of a biexciton, there are at least two channels for its optical recombination. That suggests fast recombination processes. If one (several) phonon(s) is (are) involved in a process, it is always possible to connect by an optical transition any initial state to any final one. An electric field applied parallel to the growth axis lowers the symmetry of superlattices to that of quantum wells. All the results remain valid for any bulk semiconductor with the wurtzite structure and for any wurtzite based heterostructure with identical cations or anions. (c) 2004 WILEY VCH Verlag GmbH Co. KGaA, Weinheim)
author_names: P Tronc

Yu E Kitaev

Vyacheslav P Smirnov

M A Jacobson

Gerard Neu
title: Symmetry aspects of exciton exciton interactions and biexciton transitions in wurtzite semiconductor structures
year: 2004

abstract: We experimentally demonstrate the existence of bound excitonic resonances in doped quantum wells whose electron and hole are bind by the exchange of virtual cavity photons.
author_names: Erika Cortese

L-N Tran

J-M Manceau

Giorgio Biasiol

Iacopo Carusotto

Raffaele Colombelli

Simone De Liberato
title: Cavity mediated bound excitons
venue: 2019 44th International Conference on Infrared, Millimeter, and Terahertz Waves (IRMMW THz)
year: 2019

abstract: Abstract CdWO4:Sm single crystals were studied by optical, electron paramagnetic and thermoluminescence spectroscopy in the temperature range of 4 750 K. A hopping diffusion of self trapped excitons and energy transfer to Sm3+ centres is demonstrated. The mechanism of energy transfer includes the formation of a Sm3+ bound exciton either by direct excitation or in the result of a thermally stimulated hopping diffusion of self trapped excitons as well as a sequential trapping of charge carriers near the Sm3+ ions. The energy transfer from the perturbed excitons to Sm3+ ions is controlled by an electric dipole dipole or exchange interaction and it is terminated in the temperature range of 450 650 K due to the thermal destruction of Sm3+ perturbed excitons. In the case of near surface excitations created in the energy region of high absorption coefficients by 5 eV photons, the Sm3+ emission is additionally quenched by surface induced quenching centres.
author_names: Vitali Nagirnyi

Dmitry A Spassky

Valentyn Laguta

Maksym Buryi

Marco Kirm

Sergey Omelkov

Ivo Romet

I A Tupitsyna

Pieter Dorenbos
title: Energy transfer to luminescent impurity by thermally quenching excitons in CdWO4:Sm
year: 2020