Magneto-optical spectroscopy of positively charged excitons in GaAs quantum wells

Shields, A. J.; Osborne, J.L.; Simmons, M. Y.; Pepper, M.; Ritchie, D. A.

doi:10.1103/physrevb.52.r5523

Cited by 135 publications

(90 citation statements)

References 10 publications

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“…4. Moreover this result is also in agreement with the experimental results which showed that the energy of the X + is larger 13,14 or equal 19 to the one of X − . Stébé and Moradi 6 found, on the other hand, that for a 300Å wide quantum well the binding energy of X + is lower than the one of X − which is opposite to our conclusion and to those of Ref.…”

Section: Zero Magnetic Field Trion Energysupporting

confidence: 82%

“…In spite of the large number of theoretical [1][2][3][4][5][6][7][8][9][10][11] and experimental [12][13][14][15][16][17][18][19][20][21][22][23] works published in recent years on the subject of charged excitons in quantum wells, only a very small number of them deals with positively charged excitons 4,6,10,14,16,18,19 . Different authors 4,18 used the diffusion Monte Carlo technique to calculate the dependence of the binding energy of the positively charged exciton on the well width at zero magnetic field.…”

Section: Introductionmentioning

confidence: 99%

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Positively charged magnetoexcitons in a semiconductor quantum well

2001

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A variational calculation of the lower singlet and triplet states of positively charged excitons (trions) confined to a single quantum well and in the presence of a perpendicular magnetic field is presented. We study the dependence of the energy levels and of the binding energy on the well width and on the magnetic field strength. Our results are compared with the available experimental data and show a good qualitative and quantitative agreement. A singlet-triplet crossing is found which for a 200Å wide GaAs is predicted to occur for B= 15 T.

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Section: Zero Magnetic Field Trion Energysupporting

confidence: 82%

Section: Introductionmentioning

confidence: 99%

Positively charged magnetoexcitons in a semiconductor quantum well

2001

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“…Positively charged trions T + are observed in different QW systems as well: GaAs/(Al,Ga)As, 5,12,[21][22][23][24] CdTe-based, [25][26][27] and ZnSe/(Zn,Mg)(S,Se) structures. 8,10 The triplet T + t state is stabilized in high magnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Positively versus negatively charged excitons: A high magnetic field study of CdTe/Cd1−xMgxTe quantum wells

et al. 2011

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A magneto-optical study of the energy and spin structure of charged excitons in a 20-nm-thick CdTe/Cd 0.65 Mg 0.35 Te quantum well is performed in strong magnetic fields up to 51 T. The type of resident carriers (holes or electrons) in the quantum well is controlled optically by above-barrier illumination, permitting a direct comparison of positively (T + ) versus negatively (T − ) charged excitons. The binding energies of the singlet states of these complexes behave qualitatively differently with increasing magnetic field B; namely, the binding energy decreases for T + and increases for T − with B. The triplet state of T + is identified in strong fields with a binding energy smaller than that of the T − triplet state.

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“…(By "nearly free" we mean either mobile or, more likely, weakly localized on remote charges or width fluctuations, in contrast to the "strong localization" on nearby charges.) The interacting states are the positive trion X + [6] compensated by a cyclotron excitation of the hole gas, enabling their coupling through resonant exchange of an electron-hole pair. This is observed in photoluminescence as an avoided crossing of the emission lines attributed to the X + and a cyclotron replica (CR) of the AX, as shown in Fig.…”

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confidence: 99%

Cyclotron-resonant exciton transfer between the nearly free and strongly localized radiative states of a two-dimensional hole gas in a high magnetic field

et al. 2012

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Avoided crossing of the emission lines of a nearly free positive trion and a cyclotron replica of an exciton bound to an interface acceptor has been observed in the magneto-photoluminescence spectra of p-doped GaAs quantum wells. Identification of the localized state depended on the precise mapping of the anti-crossing pattern. The underlying coupling is caused by an exciton transfer combined with a resonant cyclotron excitation of an additional hole. The emission spectrum of the resulting magnetically tunable coherent state probes weak localization in the quantum well.PACS numbers: 71.35. Ji, 71.35.Pq, 73.21.Fg, 78.20.Ls Carrier localization is attracting strong current interest fueled by anticipated applications in quantum information technology. For example, charged quantum dots may be used for storage purposes [1], while localized spins are considered as promising quantum bit candidates [2]. Particularly for the latter purpose it seems promising to study also carriers bound to defect atoms [3], as smaller extension of their wave function (compared to quantum dots) enhances protection from decoherence. Because of their weaker coupling with the nuclei [4], valence band holes appear especially attractive for information storage by localized spins.On the other hand, small spatial extent also aggravates external manipulation. For example, matrix elements for optical excitation are strongly reduced. In addition, longrange coupling between confined excitations is expected to be rather weak. A possible solution may be coupling of the localized excitations to delocalized ones. This can be obtained by placing the defects close to a quantum well, serving as an interface channel. The quantum well may also be used for efficient optical excitation, after which the photo-injected (and possibly spin-polarized) carriers are exchanged with the localization centers. For deterministic coupling between localized and delocalized excitations they must be brought in resonance where they show a pronounced avoided level crossing -very similar to the avoided crossing observed for tunnel coupled electronic states in quantum dot molecules [5].In this Letter, we report on the coupling between the nearly free and strongly localized states of different excitonic complexes formed in a two-dimensional hole gas in a high magnetic field, and study optical emission from the resulting magnetically tunable coherent state. (By "nearly free" we mean either mobile or, more likely, weakly localized on remote charges or width fluctuations, in contrast to the "strong localization" on nearby charges.) The interacting states are the positive trion X + [6] and the AX complex whose binding center A − is a bare acceptor at an interface of the well. In a high magnetic field, the difference in their binding energy is arXiv:1202.6077v1 [cond-mat.str-el]

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Magneto-optical spectroscopy of positively charged excitons in GaAs quantum wells

Cited by 135 publications

References 10 publications

Positively charged magnetoexcitons in a semiconductor quantum well

Positively charged magnetoexcitons in a semiconductor quantum well

Positively versus negatively charged excitons: A high magnetic field study of CdTe/Cd1−xMgxTe quantum wells

Cyclotron-resonant exciton transfer between the nearly free and strongly localized radiative states of a two-dimensional hole gas in a high magnetic field

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