Excitonic enhancement of the Fermi-edge singularity in a dense two-dimensional electron gas

Chen, W.; Fritze, M.; Walecki, W. J.; Nurmikko, A. V.; Ackley, D. E.; Jiao, Hong; Chang, L. L.

doi:10.1103/physrevb.45.8464

Cited by 128 publications

(68 citation statements)

References 34 publications

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“…The consistence of small ∆ data with our fit indicates that the E 2X resonance remains weakly populated enough to stay in the "atom-like" regime [16]. Also, taking f (E)=1 in the Fano lineshape formula, we can check that it fits the FES "enhancement factor" (FES PL intensity divided by its ∆ → ∞ value) measured by Chen et al in In 0.15 Ga 0.85 As QW structures [8]. Their data are indeed nicely reproduced with Γ=0.66 meV and q = 6.6 ( fig.2c).…”

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confidence: 91%

“…Emphasis was put on the anomalous temperature dependence of the singularity and on the localization of valence holes by alloy fluctuations. More recently, experiments by Chen et al [8] in In 0.15 Ga 0.85 As/AlGaAs QWs with weaker hole localization also put forward the tunability of FES, by bringing the first empty QW subband into resonance with the Fermi level. It was then proposed that empty conduction subbands could act as additional scattering channels for Coulomb processes, in qualitative agreement with many-body multi-subband numerical calculations in the infinite hole-mass approximation [9].…”

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confidence: 99%

“…This tunes the E 2 -E 1 energy separation, while E F hardly changes under illumination [13]. As seen from PL spectra of sample A (x=7.1%) in fig.1c, a FES forms and develops [8] when ∆ is decreased to zero [14]. To interpret these data, we consider the Fano resonance model depicted in fig.2a.…”

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confidence: 99%

“…Here or in ref. [8], the FES disappears, only because the PL relative minimum between E g +E F and E 2X vanishes with raised temperatures [18].…”

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confidence: 99%

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Fermi-Edge Singularities inAlxGa1−xAsQuantum Wells: Extrinsic versus Many-Body Scattering Process

Mélin

Laruelle

2000

Phys. Rev. Lett.

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confidence: 91%

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confidence: 99%

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confidence: 99%

“…Here or in ref. [8], the FES disappears, only because the PL relative minimum between E g +E F and E 2X vanishes with raised temperatures [18].…”

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confidence: 99%

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Fermi-Edge Singularities inAlxGa1−xAsQuantum Wells: Extrinsic versus Many-Body Scattering Process

Mélin

Laruelle

2000

Phys. Rev. Lett.

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“…Moreover, LDSSs have been used to observe FES, but there are two inherent shortcomings in these systems, (i) it is known that nonCoulumbian intersubband scatterings can induce FES as well [13], so it is not known exactly the relative importance of the extrinsic intersubband scattering and intrinsic many-body electron-hole interaction on the formation of FES [14] and (ii) the exact role of hole localization and reduced dimension and their relative importance on the formation of FES is not completely understood in LDSSs.…”

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confidence: 99%

Photoluminescence spectroscopy of many-body effects in heavily dopedAlxGa1−xAs

Sarkar

Ghosh

2005

Phys. Rev. B

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We present an experimental investigation of heavy doping-induced many-body effects such as band gap narrowing(BGN) and Fermi edge singularity(FES) in AlxGa1−xAs using photoluminescence(PL) spectroscopy. The band-to-band transition energy shifts to lower energies and FES-like feature in PL spectra grows with increasing electron concentration. We show that FES-like feature is a nonmonotonic function of temperature and excitation intensity. Our data lead us to suggest that a small concentration of nonequilibrated holes is required to enhance the FES-like feature in the PL spectra.PACS numbers: 71.45. Gm, 71.35.Lk, 78.55. Cr There are two most important many-body effects related to heavy doping in III-V semiconductors, (i) the shift of conduction and valence band towards each other causing band gap narrowing(BGN) due to electronelectron interaction [1], and (ii) the many-body enhancement of the oscillator strength of the optical transition near Fermi level causing Fermi edge singularity(FES), due to the response of Fermi sea to a photogenerated hole [2]. The presence of the large concentration of free carriers can cause a significant reduction of unperturbed band gap in semiconductors due to many-body interaction between electrons and holes and carrier-impurity interaction [3]. Though a detailed experimental and theoretical analysis that rigorously combines the many-body effects due to exchange-correlation and statistical fluctuation is extremely complicated problem, one can investigate the role of many-body effects on BGN in alloy semiconductor by choosing the doping concentration carefully [3]. FES is one of the most widely investigated many-body effects, first theoretically predicted by Mahan[4]. This effect was first successfully understood in terms of threshold singularity in X-ray absorption and emission spectra in simple metals [5]. In case of semiconductors, it was first observed [6] in 2D electron gas in modulation doped InP/In x Ga 1−x As quantum well and subsequently, in several other systems based on low dimensional semiconductor structures(LDSSs). It has been shown that the essential condition for observing the FES is the localization of the photogenerated holes. Typically the FES is identified as an enhancement of the oscillator strength of a transition close to Fermi level in PL spectra.Although it appears that FES is the simplest nontrivial many-body effect and understood experimentally and theoretically, upon closer inspection it seems several experimental results such as (i) observation [7,8] of FES in GaAs-based LDSSs without substantial hole localization, (ii) strong dependence[9, 10] of FES on carrier concentration and excitation intensity in GaAs-and InPbased LDSSs even in the presence of strong hole localization, and (iii) finally observation [11,12] of FES at relatively higher temperature, are not understood within the existing theoretical framework. Moreover, LDSSs have been used to observe FES, but there are two inherent shortcomings in these systems, (i) it is known that nonCoulumbian i...

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Luminescence Measurements of Two‐Dimensional Electrons in the Regime of the Integer and Fractional Quantum Hall Effects

Pulsford

Кукушкин

Hawrylak

et al. 1992

Physica Status Solidi (b)

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The radiative recombination of two-dimensional electrons is studied in GaAs-GaAIAs heterojunctions with holes localised on acceptors in strong magnetic fields. The optical measurements are emphasized as a probe of the properties of the two-dimensional electron layer. In the case of two subbands occupied, spatial changes in the self-consistent potential due to a population in the second subband are demonstrated. In the regime of the fractional quantum Hall effect, downward cusps occur in the mean energy of the luminescence at fractional filling factors and values for the quasiparticle energy gaps are derived.

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Excitonic enhancement of the Fermi-edge singularity in a dense two-dimensional electron gas

Cited by 128 publications

References 34 publications

Fermi-Edge Singularities inAlxGa1−xAsQuantum Wells: Extrinsic versus Many-Body Scattering Process

Fermi-Edge Singularities inAlxGa1−xAsQuantum Wells: Extrinsic versus Many-Body Scattering Process

Photoluminescence spectroscopy of many-body effects in heavily dopedAlxGa1−xAs

Luminescence Measurements of Two‐Dimensional Electrons in the Regime of the Integer and Fractional Quantum Hall Effects

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