Dynamical equilibrium between excitons and trions in CdTe quantum wells in high magnetic fields

Jeukens, Cécile R. L. P. N.; Christianen, Peter C. M.; Maan, J.C.; Yakovlev, D. R.; Ossau, W.; Кочерешко, В. П.; Wójtowicz, T.; Karczewski, G.; Kossut, J.

doi:10.1103/physrevb.66.235318

Cited by 28 publications

(29 citation statements)

References 45 publications

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“…For example, many papers were devoted to theoretical and experimental studies on the binding energy under different conditions and in different materials 2,3,4,5,6 . Detailed investigations were also performed on the selection rules 7,8,9 , and on the dynamics 10,11,12,16 , in particular the formation time 13,14,15 and spin relaxation 11,17 . Most of those properties are well established and can be used for identification purposes.…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence ofp-doped quantum wells with strong spin splitting

et al. 2004

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The spectroscopic properties of a spin polarized two-dimensional hole gas are studied in modulation doped Cd1−xMnxTe quantum wells with variable carrier density up to 5 10 11 cm −2 . The giant Zeeman effect which is characteristic of diluted magnetic semiconductors, induces a significant spin splitting even at very small values of the applied field. Several methods of measuring the carrier density (Hall effect, filling factors of the Landau levels at high field, various manifestations of MossBurstein shifts) are described and calibrated. The value of the spin splitting needed to fully polarize the hole gas, evidences a strong enhancement of the spin susceptibility of the hole gas due to carriercarrier interaction. At small values of the spin splitting, whatever the carrier density (non zero) is, photoluminescence lines are due to the formation of charged excitons in the singlet state. Spectral shifts in photoluminescence and in transmission (including an "excitonic Moss-Bustein shift") are observed and discussed in terms of excitations of the partially or fully polarized hole gas. At large spin splitting, and without changing the carrier density, the singlet state of the charged exciton is destabilized in favour of a triplet state configuration of holes. The binding energy of the singlet state is thus measured and found to be independent of the carrier density (in contrast with the splitting between the charged exciton and the neutral exciton lines). The state stable at large spin splitting is close to the neutral exciton at low carrier density, and close to an uncorrelated electron-hole pair at the largest values of the carrier density achieved. The triplet state gives rise to a characteristic double-line structure with an indirect transition to the ground state (with a strong phonon replica) and a direct transition to an excited state of the hole gas.

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Section: Introductionmentioning

confidence: 99%

Photoluminescence ofp-doped quantum wells with strong spin splitting

et al. 2004

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“…At temperatures as low as 1.6 K only the lower Zeeman sublevels of the excitons and electrons are populated in the magnetic field. But the singlet trion state is formed from the higher exciton and electron sublevels [1]. At higher temperatures these sublevels start to get populated which leads to the increase in the trion PL and subsequently to decrease in the PL of the neutral exciton (the integral intensity does not change).…”

Section: Luminescencementioning

confidence: 99%

“…The splitting between optically dark and optically active excitons was taken to be δ X = 0.2 meV [1]. The parameters we used are similar to those in [5] for GaAs QWs and in [6] for ZnSe based QWs, only scaled according to the exciton binding energy.…”

Section: Model Calculation Of the Exciton-trion Systemmentioning

confidence: 99%

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Temperature Dependence of Exciton and Trion States in CdTe Quantum Well at High Magnetic Fields

et al. 2005

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“…Consequently, existing models discriminate the formation channel yielding trions of opposite charge. Current models for trion formation [18,19] surmise that trions are exclusively formed through a bimolecular process, i.e., the coalescence of an exciton and a charged free carrier. While this is conceivable at low densities, nothing attests that genuine formation of the trion from an unbound electron-hole plasma (trimolecular formation) is negligible at higher densities.…”

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Dynamics of Trion Formation inInxGa1−xAsQuantum Wells

et al. 2009

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We show a double path mechanism for the formation of charged excitons (trions); they are formed through bi-and trimolecular processes. This directly implies that both negatively and positively charged excitons coexist in a quantum well, even in the absence of excess carriers. The model is substantiated by time-resolved photoluminescence experiments performed on a very high quality In x Ga 1Àx As quantum well sample, in which the photoluminescence contributions at the energy of the trion and exciton and at the band edge can be clearly separated and traced over a broad range of times and densities. The unresolved discrepancy between the theoretical and experimental radiative decay time of the exciton in a doped semiconductor quantum well is explained by the same model. Positively and negatively charged excitons (X þ and X À trions) [1,2] are usually compared to their atomic counterpart ions of helium He þ and hydrogen H À , respectively. In astronomy, the dynamics of the formation of these atomic ions is of great importance [3]; indeed, H À is the primary source of the continuum opacity in most stellar photospheres and contributes to the production of hydrogen and other elements in various parts of the Universe. Additionally, the abundance of free electrons in the solar atmosphere is indirectly measured in terms of H À concentration. In semiconductor quantum wells (QWs), trions show a number of properties very similar to excitons [4], such as strong coupling in microcavities [5], absorption bleaching [6,7], transport [8] and diffusion [9] properties, and radiative recombination efficiency [10,11], and thus have attracted considerable interest. Moreover, trions promise to play a key role in future applications, notably in quantum-information science [12] and in the future development of all-spin-based scalable quantum computers [13,14]. They are correlated with excitons and the free carrier plasma and offer the possibility to test a model of formation of three-particle complexes.The formation process of neutral excitons (X) in QWs has been extensively investigated over the past two decades [15,16] and recently shown to be strongly density-and temperature-dependent [17]. This is a bimolecular process, in which an electron (e) and a hole (h) are bound by Coulomb interaction with the emission of the appropriate phonon. Conversely, the formation process of trions has been much less studied. It is largely believed that trions can be formed only if a population of excess carriers is trapped in the well, producing exclusively trions with the same charge. Consequently, existing models discriminate the formation channel yielding trions of opposite charge. Current models for trion formation [18,19] surmise that trions are exclusively formed through a bimolecular process, i.e., the coalescence of an exciton and a charged free carrier. While this is conceivable at low densities, nothing attests that genuine formation of the trion from an unbound electron-hole plasma (trimolecular formation) is negligible at higher densities.In...

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Dynamical equilibrium between excitons and trions in CdTe quantum wells in high magnetic fields

Cited by 28 publications

References 45 publications

Photoluminescence ofp-doped quantum wells with strong spin splitting

Photoluminescence ofp-doped quantum wells with strong spin splitting

Temperature Dependence of Exciton and Trion States in CdTe Quantum Well at High Magnetic Fields

Dynamics of Trion Formation inInxGa1−xAsQuantum Wells

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