Photoluminescence from fractional quantum Hall systems: Role of separation between electron and hole layers

Abstract

The photoluminescence (PL) spectrum of a two-dimensional electron gas (2DEG) in the fractional quantum Hall regime is studied as a function of the separation $d$ between the electron and valence hole layers. The abrupt change in the response of the 2DEG to the optically injected hole at $d$ of the order of the magnetic length $\lambda$ results in a complete reconstruction of the PL spectrum. At $d<\lambda$, the hole binds one or two electrons to form neutral ($X$) or charged ($X^{-}$) excitons, and the PL spectrum probes the lifetimes and binding energies of these states rather than the original correlations of the 2DEG. At $d>2\lambda$, depending on the filling factor $\nu$, the hole either decouples from the 2DEG to form an ``uncorrelated'' state $h$ or binds one or two Laughlin quasielectrons (QE) to form fractionally charged excitons $h$QE or $h$QE${}_2$. The strict optical selection rules for bound states are formulated, and the only optically active ones turn out to be $h$, $h$QE* (an excited state of the dark $h$QE), and $h$QE${}_2$. The ``anyon exciton'' $h$QE${}_3$ suggested in earlier studies is neither stable nor radiative at any value of $d$. The critical dependence of the stability of different states on the presence of QE's in the 2DEG explains the observed anomalies in the PL spectrum at $\nu =\frac{1}{3}$ and $\frac{2}{3}$.

12 pages, 5 figures, submitted to PRB

References in corpus (5)

• Charged Excitons in a Dilute 2D Electron Gas in a High Magnetic Field
• Quasiparticle Interactions in Fractional Quantum Hall Systems: Justification of Different Hierarchy Schemes
• Two-dimensional charged electron-hole complexes in magnetic fields: Keeping magnetic translations preserved
• Energy spectra of fractional quantum Hall systems in the presence of a valence hole
• Energy spectra and photoluminescence of charged magneto-excitons

Cited by in corpus (9)

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• The Hierarchy of Incompressible Fractional Quantum Hall States
• Negatively Charged Excitons and Photoluminescence in Asymmetric Quantum Well
• Quasiexcitons in Incompressible Quantum Liquids
• Energy, interaction, and photoluminescence of spin-reversed quasielectrons in fractional quantum Hall systems
• Photoluminescence of the incompressible Laughlin liquid: Excitons, charged excitons, and fractionally charged excitons
• Reversed-Spin Quasiparticles in Fractional Quantum Hall Systems and Their Effect on Photoluminescence
• Electron-Hole Systems in Narrow Quantum Wells: Excitonic Complexes and Photoluminescence
• Probing fractional quantum Hall effect by photoluminescence