Exciton diamagnetic shift in semiconductor nanostructures

Walck, Scott N.; Reinecke, T. L.

doi:10.1103/physrevb.57.9088

Cited by 151 publications

(137 citation statements)

References 14 publications

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“…Exciton ͑biexciton͒ diamagnetic shifts were measured for a large number of dots in all the samples by measuring the change in the average energy of the exciton ͑biexciton͒ doublet with increasing field. The diamagnetic shifts were found to be proportional to the square of the applied field as expected; 22 the coefficients of proportionality for each dot are plotted in Fig. 3 as a function of the corresponding dot emission energy.…”

mentioning

confidence: 89%

Inversion of exciton level splitting in quantum dots

et al. 2005

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The demonstration of degeneracy of the exciton spin states is an important step towards the production of entangled photons pairs from the biexciton cascade. We measure the fine structure of exciton and biexciton states for a large number of single InAs quantum dots in a GaAs matrix; the energetic splitting of the horizontally and vertically polarised components of the exciton doublet is shown to decrease as the exciton confinement decreases, crucially passing through zero and changing sign. Thermal annealing is shown to reduce the exciton confinement, thereby increasing the number of dots with splitting close to zero.Comment: 12 pages, 4 figure

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mentioning

confidence: 89%

Inversion of exciton level splitting in quantum dots

et al. 2005

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“…One should note that this expression is strictly valid only for the systems with translational symmetry in the plane perpendicular to the magnetic field (i.e., in bulk or quantum wells) 7 . By applying this formula also to the case of QDs we obtained the values of the spatial extension of the excitonic wave function in normal configuration for CdSe and CdTe QDs as r 2 = 2.4 nm and 3.1 nm, respectively.…”

Section: Zeeman Effect and Diamagnetic Shiftmentioning

confidence: 99%

“…We particularly focus on differences between excitons of various charge states: their binding energy, g-factor and diamagnetic shift. These quantities have been already measured for single quantum dots [7][8][9][10][11][12][13][14][15][16][17] , but have not been analyzed in terms of variation across the QD population.…”

Section: Introductionmentioning

confidence: 99%

Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots

Kobak

Smoleński

Goryca

et al. 2016

J. Phys.: Condens. Matter

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We present a comparative study of two self-assembled quantum dot (QD) systems based on II-VI compounds: CdTe/ZnTe and CdSe/ZnSe. Using magneto-optical techniques we investigated a large population of individual QDs. The systematic photoluminescence studies of emission lines related to the recombination of neutral exciton X, biexciton XX, and singly charged excitons (X + , X − ) allowed us to determine average parameters describing CdTe QDs (CdSe QDs): X-XX transition energy difference 12 meV (24 meV); fine-structure splitting δ1 = 0.14 meV (δ1 = 0.47 meV); g-factor g = 2.12 (g = 1.71); diamagnetic shift γ = 2.5 µeV/T 2 (γ = 1.3 µeV/T 2 ). We find also statistically significant correlations between various parameters describing internal structure of excitonic complexes.

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“…18,47 The diamagnetic shifts of the "bright" exciton states were measured and corresponded to comparatively similar values of the diamagnetic coefficients (α 1 ≈ 7 μeV/T 2 , α 4 ≈ 6 μeV/T 2 ) in a transverse and a longitudinal magnetic field. As the diamagnetic shift is a sensitive probe of the spatial confinement in a direction transverse to the magnetic field, 48 we infer from its insensitivity to the magnetic field orientation that the spatial extent of the exciton wave function is close to isotropic in our pyramidal quantum dots. This qualitative analysis of the diamagnetic shifts corroborates our interpretation of the small values of the Zeeman splitting for a transverse magnetic field as resulting from a peculiar effect of symmetry elevation, which is particularly effective in these pyramidal quantum dots, as was demonstrated in the analysis of their photoluminescence spectra.…”

Section: Discussionmentioning

confidence: 99%

“…This general approach was initially developed by Kohn and Luttinger in order to describe the cyclotron resonances of holes in a germanium or a silicium crystal. 4,5 The magneto-optical properties of excitons in GaAs/Al x Ga 1−x As quantum wells have been extensively studied both experimentally [6][7][8][9] and theoretically, [10][11][12] thereby highlighting the importance of valence-band mixing and the paramagnetic and diamagnetic contributions to both the Zeeman splitting energy and the diamagnetic shift of the excitons. Despite these results on magnetoexcitons in quantum wells, the interplay between the Coulomb and the Zeeman interactions has largely eluded the observation in magnetophotoluminescence studies of the fine-structure splitting of excitons in single semiconductor QDs.…”

Section: Introductionmentioning

confidence: 99%

Intertwining of Zeeman and Coulomb interactions on excitons in highly symmetric semiconductor quantum dots

Oberli

2012

Phys. Rev. B

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We present an experimental study and develop a group theoretical analysis of the Zeeman effect on excitons in pyramidal semiconductor quantum dots possessing the symmetries of the C 3v point group. The magnetic field dependence of the emission pattern originating from neutral exciton states is investigated in both the Faraday and Voigt configurations. The Zeeman doublet splitting of the "bright" exciton states varies linearly with the magnetic field strength in each configuration while the intensity of the "dark" exciton transitions exhibit a nonlinear dependence. We demonstrate that these observations originate from the intertwining of the Zeeman and Coulomb interactions, which provides clear spectral signatures of this effect for highly symmetric quantum dots. We uncover a large anisotropy of the Zeeman doublet splittings for longitudinal and transverse magnetic fields, revealing the ubiquitous role of a symmetry elevation in our pyramidal quantum dots. These results suggest that the common description of the Zeeman effect based on effective g factors for electrons and holes must be revised when dealing with exciton complexes.

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Exciton diamagnetic shift in semiconductor nanostructures

Cited by 151 publications

References 14 publications

Inversion of exciton level splitting in quantum dots

Inversion of exciton level splitting in quantum dots

Comparison of magneto-optical properties of various excitonic complexes in CdTe and CdSe self-assembled quantum dots

Intertwining of Zeeman and Coulomb interactions on excitons in highly symmetric semiconductor quantum dots

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