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Wyszukujesz frazę "71.35.Pq" wg kryterium: Temat


Tytuł:
Trion Binding Energies and Wave Functions in Doped Quantum Wells
Autorzy:
Gładysiewicz, A.
Wójcik, K.
Wójs, A.
Quinn, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/2043713.pdf
Data publikacji:
2005-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
Opis:
The energy spectra of negative trions (X$\text{}^{-}$=2e+h) in one-sided doped GaAs quantum wells are calculated. The maps of the trion binding energyΔ as a function of well width w, electron concentration n, and the magnetic field B are obtained. The dependence of the trion ground state ("bright singlet" versus "dark triplet") on those parameters is established.
Źródło:
Acta Physica Polonica A; 2005, 108, 4; 669-674
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoluminescence of Charged Excitons in Fractional Quantum Hall Systems
Autorzy:
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/2038337.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Ji
71.35.Ee
71.35.Pq
Opis:
Neutral and charged excitonic complexes formed in integral and fractional quantum Hall systems are discussed. They are bound states of a small number of charged quasiparticles (e.g., conduction electrons and valence holes, reversed-spin electrons and spin holes, Laughlin quasielectrons and quasiholes, composite fermions) that occur in an electron system under specific conditions (electron density, well width, electric and magnetic fields, etc.). The examples are interband neutral and charged excitons, "anyon excitons", spin waves, skyrmions, and "skyrmion excitons". Their possible decay processes include radiative recombination, experimentally observed in photoluminescence or far infrared emission, or spin transitions, important in the context of nuclear spin relaxation.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 355-366
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative Numerical Analysis of Quasi-Two-Dimensional Negative and Positive Trions in High Magnetic Fields
Autorzy:
Trojnar, A.
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/1812000.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
71.10.Pm
Opis:
Exact diagonalization calculations in the Haldane spherical geometry are carried out for the three-body Coulomb problem in a quasi-two-dimensional quantum well, in the presence of perpendicular magnetic field. Simultaneous inclusion of several Landau levels and quantum well subbands in the configuration-interaction basis allowed for quantitative description of the coupling between the in-plane dynamics (governed by interplay of cyclotron quantization and Coulomb interactions) and single-particle excitations in the normal direction. The energy spectra of negative and positive trions are compared in symmetric and asymmetric wells with realistic widths and carrier concentrations. Effects of nearby impurities are also studied.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1411-1416
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Localization of Excitons in the Wetting Layer Accompanying Self-Assembled InAs/GaAs Quantum Dots
Autorzy:
Babinski, A.
Raymond, S.
Wasilewski, Z.
Lapointe, J.
Potemski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2038091.pdf
Data publikacji:
2004-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
71.70.Ej
Opis:
A wetting layer is a narrow, highly strained quantum well, which accompanies quantum dots grown in Stranski-Krastanow mode. Its importance for a full description of the quantum dots properties has recently been pointed out. It has been shown for example that excitons can be localized by potential fluctuations in the wetting layer. This is equivalent to the formation of "natural" quantum dots in the WL. Excitonic emission from the single dots formed in the wetting layer accompanying the InAs/GaAs self-assembled quantum dots has been investigated in a high magnetic field (up to 23 T). Quadruplet splitting of the investigated emission line has been observed. The attribution of the emission line to the recombination of negatively charged exciton is discussed.
Źródło:
Acta Physica Polonica A; 2004, 105, 6; 547-552
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculation of Exciton and Trion Absorption Spectra in High Magnetic Fields
Autorzy:
Gładysiewicz, A.
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/2046912.pdf
Data publikacji:
2006-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
71.10.Pm
Opis:
Density of states and absorption spectrum of narrow quantum wells containing a small number of free electrons and subject to a high magnetic field are calculated numerically. The effect of an additional, second electron on the photoexcited electron-hole pair is analyzed. In density of states, the exciton-electron interaction fills the gaps between the Landau levels and yields additional discrete peaks corresponding to bound trions. In absorption, interaction with the additional free electron has no effect on the position or intensity of the main sequence of excitonic peaks. However, it gives rise to additional weaker trion peaks, both in the lowest and higher Landau levels.
Źródło:
Acta Physica Polonica A; 2006, 110, 2; 183-188
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Many-Body Interactions in the CdTe-Based Quantum Well under Strong Optical Excitation
Autorzy:
Płochocka, P.
Kossacki, P.
Piechal, B.
Maślana, W.
Golnik, A.
Cibert, J.
Tatarenko, S.
Gaj, J. A.
Powiązania:
https://bibliotekanauki.pl/articles/2038365.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.De
71.35.Pq
78.47.+p
Opis:
We performed pump-probe time-resolved absorption measurements on a modulation p-doped (Cd,Mn)Te quantum well. The density of the 2D hole gas was controlled, in the 10$\text{}^{10}$ cm$\text{}^{-2}$ range, by additional cw illumination. Interactions between photocreated neutral (X) and charged (X$\text{}^{+}$) excitons and the 2D hole gas were analyzed. We found that the strongest effect is the influence of the carriers on both X and X$\text{}^{+}$ optical resonances. Neutral and charged excitons are screened by holes, which results in the decrease in their intensities. We conclude from polarization resolved experiments that this screening is spin-dependent: it is more efficient between holes with opposite spins. Binding holes into the charged excitons reduces the screening of the neutral excitons and leads to an enhancement of the neutral exciton intensity. We also analyzed weaker effects, due to exciton-exciton interaction, at a constant hole density. We found that the reduction of the neutral exciton intensity due to two different mechanisms (phase-space filling and biexciton formation) is almost equal. We observed a spin-dependent blue shift of the neutral exciton line in the presence of a population of neutral excitons created by the pump pulse. Due to the attractive interaction between excitons with opposite spins, the corresponding shift of the neutral exciton is smaller than that observed due to the interaction between excitons with the same spins.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 413-422
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Fractional Quasiexcitons in Photoluminescence of Quantum Hall Liquids
Autorzy:
Wójs, A.
Gładysiewicz, A.
Quinn, J. J.
Powiązania:
https://bibliotekanauki.pl/articles/2044555.pdf
Data publikacji:
2005-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
71.35.Ji
73.43.-f
71.10.Pm
Opis:
Realistic calculations of photoluminescence spectra for a 20 nm quantum well at a filling factorν=1/3 are presented. The new states formed from charged excitons (trions) by correlation with the surrounding electrons are identified. These "quasiexcitons" differ from usual excitons and trions by having fractionally charged constituents. Their binding energies and emission intensities depend on the involved trion, leading to discontinuity in photoluminescence.
Źródło:
Acta Physica Polonica A; 2005, 108, 5; 923-928
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Combined Exciton-Cyclotron Resonance in Photoluminescence of a Two-Dimensional Hole Gas
Autorzy:
Jadczak, J.
Bryja, L.
Płochocka, P.
Wójs, A.
Misiewicz, J.
Maude, D.
Potemski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1791299.pdf
Data publikacji:
2009-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Mf
71.35.Ji
71.35.Pq
78.20.Ls
Opis:
A two-dimensional hole gas in an asymmetric GaAs/$Ga_{1-x}Al_{x}As$ quantum well is studied by polarization-resolved photoluminescence in high magnetic fields (up to B = 20 T) and at low temperatures (down to T = 50 mK). In addition to the previously reported dominant emission channels of various free and acceptor-bound trions, the high-energy hole cyclotron replicas of the bound states are now also observed, corresponding to the combined exciton-cyclotron resonance. Identification of different transitions in the rich, multi-peak spectra was possible by the analysis of optical selection rules and comparison of the experimental spectra with realistic numerical calculations.
Źródło:
Acta Physica Polonica A; 2009, 116, 5; 852-853
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Time-Resolved Studies of Excitonic Dynamics in a Wide II-VI Quantum Well by a Femtosecond Pump-Probe Reflectivity
Autorzy:
Trajnerowicz, A.
Golnik, A.
Kossacki, P.
Pacuski, W.
Wojtowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/2047018.pdf
Data publikacji:
2006-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.De
71.35.Pq
78.47.+p
Opis:
We present time-dependent reflectance spectra of wide (Cd,Mn)Te/(Cd,Mg)Te quantum wells. Interactions between excitons, trions, and carriers are studied for exciton densities up to 10$\text{}^{11}$ cm$\text{}^{-2}$. The resonant excitation at different excitonic lines is analyzed.
Źródło:
Acta Physica Polonica A; 2006, 110, 3; 395-401
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evidence of Singlet-Triplet Crossing in Photoluminescence of Positively Charged Excitons in GaAs Quantum Wells
Autorzy:
Bryja, L.
Wójs, A.
Jadczak, J.
Misiewicz, J.
Płochocka, P.
Potemski, M.
Reuter, D.
Wieck, A.
Powiązania:
https://bibliotekanauki.pl/articles/1811918.pdf
Data publikacji:
2008-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Mf
71.35.Ji
71.35.Pq
78.20.Ls
Opis:
Positively charged excitons in a two-dimensional hole gas in symmetric and asymmetric GaAs/$Ga_{1-x}Al_{x}As$ quantum wells are studied in polarization-resolved photoluminescence experiments in high magnetic fields B (up to 23 T) and low temperatures (down to 300 mK). The experiments are accompanied by numerical calculations of a real structure. The whole family of trions (the singlet and a pair of triplets) are observed. The Coulomb energies crossing of singlet and triplet is found: hidden in symmetric and visible in asymmetric structures.
Źródło:
Acta Physica Polonica A; 2008, 114, 5; 1073-1077
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Energy and Optical Absorption Spectra of Multiply Charged Anisotropic Quantum Boxes
Autorzy:
Trojnar, A.
Małachowski, T.
Wójs, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047372.pdf
Data publikacji:
2007-08
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.22.-f
78.67.Hc
71.35.-y
71.35.Pq
Opis:
Using a simple model of a two-dimensional rectangular quantum box we study the effects of size and anisotropy on the energy and photoluminescence spectra of neutral and charged quantum dots. The competition of symmetries and energy/length scales of the free exciton or trion and of the confining potential is analyzed. The numerical calculations consisted of the diagonalization of the few-electron-hole Hamiltonian matrices in the full configuration-interaction basis, with the simultaneous resolution of the conserved orbital and spin quantum numbers.
Źródło:
Acta Physica Polonica A; 2007, 112, 2; 173-176
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exciton Exchange between Nearly-Free and Acceptor-Bound States of a Positive Trion Assisted by Cyclotron Excitation
Autorzy:
Jadczak, J.
Bryja, L.
Wójs, A.
Bartsch, G.
Yakovlev, D. R.
Bayer, M.
Plochocka, P.
Potemski, M.
Reuter, D.
Wieck, A.
Powiązania:
https://bibliotekanauki.pl/articles/2047925.pdf
Data publikacji:
2011-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
73.20.Mf
71.35.Ji
71.35.Pq
78.20.Ls
Opis:
In magneto-photoluminescence spectra of a two-dimensional hole gas in a GaAs quantum well we observe coupling of two different radiative states. The pair of coupled states are an acceptor-bound trion AX$\text{}^{+}$ and an essentially free (only weakly localized by a shallow lateral potential) trion X$\text{}^{+}$, brought into resonance by an additional cyclotron excitation controlled by the magnetic field. The coupling mechanism is the exciton transfer, and the optical signature is a clear anticrossing of the emission lines of an X$\text{}^{+}$ and a cyclotron replica of the AX$\text{}^{+}$.
Źródło:
Acta Physica Polonica A; 2011, 119, 5; 600-601
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charging Effects in Self-Assembled CdTe Quantum Dots
Autorzy:
Kłopotowski, Ł.
Powiązania:
https://bibliotekanauki.pl/articles/1492785.pdf
Data publikacji:
2011-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.67.Hc
32.60.+i
71.35.Pq
71.55.Gs
Opis:
In this review, we summarize our achievements in controlling and understanding the charging effects in single self-assembled CdTe quantum dots. We start with analysis of the single dot emission spectrum. For excitation densities small enough to ensure only s-shell recombination, we find that for all dots (also those reported by other groups) the same transition sequence is observed. Namely, the neutral exciton recombination has the highest energy while charged exciton and biexciton transitions are redshifted. This observation remains in a stark contrast to self-assembled InGaAs dots, where charged complexes may appear also on the high energy side of the neutral exciton. We explain the universality of the transition sequence assuming domination of the Coulomb correlations over direct, single particle interactions. Furthermore, through measurement of the recombination rates, we gain access to electron and hole wave functions and their redistributions upon changing the dot occupancy. We find that the electron wave function is rather stiff, while the hole wave function is rather soft owing to enhanced correlations in the valence band. We then corroborate these conclusions with the Stark spectroscopy, where we analyze energy shifts due to electric field imposed on dots embedded in a field effect or diode structure. Finally, we use these structures to obtain controllable tuning of the charge state. We discuss different approaches to this task and find the best tuning efficiency for a structure with enhanced valence band confinement.
Źródło:
Acta Physica Polonica A; 2011, 120, 5; 819-829
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Internal Transitions of Charged Excitons in AlGaAs/GaAs Lateral Fluctuation Quantum Dots
Autorzy:
Meining, C. J.
Whiteside, V. R.
McCombe, B. D.
Nickel, H. A.
Petrou, A.
Tischler, J. G.
Bracker, A. S.
Gammon, D.
Dzyubenko, A. B.
Powiązania:
https://bibliotekanauki.pl/articles/2038344.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Ji
71.35.Pq
73.21.La
78.55.Cr
78.67.Hc
Opis:
Low temperature measurements of magneto-photoluminescence and optically detected resonance spectroscopy in magnetic fields up to 10~T were carried out on GaAs/Al$\text{}_{0.3}$Ga$\text{}_{0.7}$As quantum well samples grown by molecular beam epitaxy with lateral fluctuation quantum dots produced by growth interruption. Monolayer fluctuations of the quantum well width form lateral quantum dots for which confinement energies are less than Coulomb correlation energies. Five different width quantum wells (2.8-14.1 nm) were grown in a single sample, doped in the barriers with Si donors to allow for photoluminescence of both excitons and trions. We report studies of the optically detected resonance spectra associated with the ensemble photoluminescence of all of the wells including observation of bound-to-continuum internal transitions of trions, both singlet and triplet, and electron cyclotron resonance for the wider wells, which also show a clear bound-to-bound triplet transition. The latter is forbidden by magnetic translational invariance, but can be seen in these samples because this symmetry is broken by the lateral fluctuations, whose characteristic dimensions are greater than the trion orbit size. The two narrowest wells show strong broad optically detected resonance signals associated with inhomogeneously broadened internal transitions of the strongly correlated trions in the lateral dots. The optically detected resonance signals peak well below the calculated positions of electron cyclotron resonance. As expected for localized carriers and excitons, there is no free electron cyclotron resonance. We also present preliminary measurements of optically detected resonance spectra from a single dot.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 383-393
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Many-Body Interaction Evidenced through Exciton-Trion-Electron Correlated Dynamics
Autorzy:
Portella-Oberli, M. T.
Berney, J. H.
Deveaud, B.
Ciulin, V.
Kutrowski, M.
Wojtowicz, T.
Powiązania:
https://bibliotekanauki.pl/articles/2038371.pdf
Data publikacji:
2004-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
71.35.Pq
78.47.+p
42.65.-k
78.67.De
Opis:
Interactions among excitons, trions, and electrons are studied in CdTe modulation-doped quantum wells. These many-body interactions are investigated through the nonlinear dynamical properties in the excitonic complexes using time and spectrally resolved pump and probe techniques. This study is performed as a function of temperature and densities of excitons, trions, and electrons. The results reveal that the nonlinearities induced by trions differ from those induced by excitons and moreover they are mutually correlated. The correlated behavior of excitons and trions manifests itself by crossed trion-exciton effects. We propose that the main source of these correlations is due to the presence of electrons in the quantum well and that its physical origin is the Pauli exclusion-principle. We find that, at 5 K, trions are formed from excitons within 10 ps; at 20 K a thermal equilibrium is reached within 5 ps.
Źródło:
Acta Physica Polonica A; 2004, 106, 3; 423-434
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł

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