Coulomb Correlations and Biexciton Signatures in Coherent Excitation Spectroscopy of Semiconductor Quantum Wells

Finger, E.; Kraft, Stephan; Hofmann, Martin R.; Meier, Torsten; Koch, S. W.; Stolz, W.; Rühle, W. W.; Wieck, A. D.

doi:10.1002/1521-3951(200211)234:1<424::aid-pssb424>3.0.co;2-v

Cited by 15 publications

(20 citation statements)

References 29 publications

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“…The stripes occur because free pairs strongly couple to the excitonic resonances, resulting in a dominant signal at the exciton (19). They have previously been observed in coherent excitation spectroscopy (38) and magnitude 2DFTS (23).…”

Section: Resultsmentioning

confidence: 99%

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

Zhang

Кузнецова

Meier

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

116

113

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Optical 2D Fourier transform spectroscopy (2DFTS) provides insight into the many-body interactions in direct gap semiconductors by separating the contributions to the coherent nonlinear optical response. We demonstrate these features of optical 2DFTS by studying the heavy-hole and light-hole excitonic resonances in a gallium arsenide quantum well at low temperature. Varying the polarization of the incident beams exploits selection rules to achieve further separation. Calculations using a full many-body theory agree well with experimental results and unambiguously demonstrate the dominance of many-body physics.excitons ͉ many-body effects ͉ ultrafast O ptical excitation of a direct gap semiconductor, such as gallium arsenide (GaAs), produces electron-hole pairs. The Coulomb attraction between the electron and hole can result in a bound state, known as an exciton, with a hydrogenic wavefunction for the relative coordinate. Excitons have a large oscillator strength because of the proximity of the electron and hole and thus can dominate the absorption spectrum close to the fundamental band gap. In GaAs heterostructures, the exciton binding energy is of order 10 meV; thus, excitonic resonances appear only at low temperatures. Excitons and unbound electron-hole pairs exhibit dynamics on a femtosecond-to-picosecond time scale. These timescales, combined with the strong interaction with light, make ultrafast spectroscopy an ideal tool for studying carrier dynamics in semiconductors.Over the last two decades, excitonic resonances in semiconductors have been studied extensively by using ultrafast spectroscopy, primarily transient four-wave-mixing (TFWM) (1, 2). The measurements clearly showed signatures of many-body effects. The first and most prominent was a signal for the ''wrong'' time delay in a two-pulse TFWM experiment. Theoretically, such signals could arise from several effects including local fields (3, 4), biexcitons (5), excitation-induced dephasing (6, 7), or excitation-induced shift (8). Time resolving the signal also provided evidence for many-body contributions (9, 10), although it did not resolve the ambiguity regarding the underlying phenomena.Recent results using optical 2D Fourier transform spectroscopy (2DFTS) to study the exciton resonances have shown that much more information is obtained, promising a more stringent test of the theory (11). 2DFTS traces its roots to NMR (12). Recently, there has been significant progress in translating multidimensional NMR techniques into the infrared and optical domains for the study of vibrations (13) and electronic excitations (14-16) in molecules. Although the usefulness of adding a second dimension was recognized in TWFM studies of semiconductors (17-20), only the intensity of the emitted signal, not the phase-resolved electric field, was measured. The transient absorption experiments clearly show that detecting only the real part of the emitted field is advantageous (21, 22), but the effects of inhomogeneous broadening cannot be removed. 2DFTS combines the best...

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Section: Resultsmentioning

confidence: 99%

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

Zhang

Кузнецова

Meier

et al. 2007

Proc. Natl. Acad. Sci. U.S.A.

116

113

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“…3(c) and deduce the biexciton binding energies for XX AA ; XX AB ; and XX BB were 15.6AE0.5, 16.6AE0.3, and 4.7AE0.3 meV [18]. Heterobiexcitons XX AB have been observed actually in ZnSe multiple quantum wells (QWs) [14], bulk GaN [15] by FWM, and bulk ZnO by two-photon reabsorption [16], and GaAs single QW by coherent excitation spectroscopy [17].…”

Section: Biexcitons In Znomentioning

confidence: 87%

Polarization and wave-vector-dependent measurements by four-wave mixing in ZnO: valence-band ordering and biexcitons

Adachi

2005

Journal of Luminescence

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“…(11) and one must resort to an approximate solution for simulation of the 2D spectrum (13). Here we use 1S trial wave function (8) to minimize the biexciton energy (11) with respect to the variational parameter (biexciton radius) a XX .…”

Section: Pss-bcommentioning

confidence: 94%

“…Non-linear optical processes are sensitive to the interactions between quasiparticles and provide direct information on processes that are inaccessible with linear spectroscopic techniques. Recently some novel 2D correlation spectroscopic techniques have been applied to study exciton and biexciton formation, their dynamics and transport in bulk semiconductors, quantum wells and quantum dots [11][12][13][14]. In these time domain experiments, a train of well separated optical pulses excites the sample and the generated x (3) signal is heterodyne detected in one of the possible phase matching conditions.…”

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confidence: 99%

Coherent manipulation of quadrupole biexcitons in cuprous oxide by 2D femtosecond spectroscopy

Roslyak

Aparajita

Birman

et al. 2011

Physica Status Solidi (b)

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We propose using coherent optical spectroscopy to study and control optically-forbidden (dark) biexciton states in crystals of cuprous oxide. These states are revealed in the correlation spectra cross resonances due to coherence with the quadrupole allowed 1S exciton manifold. The signal is obtained by means of sum-over-state formalism and comparing equations of motion for the weakly interacting quadrupole excitons with their analogue of non-interacting quasiparticles. The dephasing mechanisms include rapid Auger relaxation of biexcitons which allegedly impedes the Bose-Einstein condensation of quadrupole excitons. An interesting effect attributed to the deviation of the quadrupole excitons from the ortho-para excitons picture is that the positions of the biexciton resonances are defined by the energy splitting between G þ 5;yz and G þ 5;xz excitons and can be tuned by an external perturbation. Possible quantum computing and lasing applications of the quadrupole induced chirality effects of the excitons and biexcitons, and coherence between exciton/biexciton manifolds are discussed. '' Equal parity of the conduction and valence band states produces dipole-forbidden, quadrupole-allowed 1S exciton which is characterized by a long radiative life-time depending on a dominating dephasing mechanism and varies from ns to ps. At low exciton density the measured life-time (%1.7 ns) is determined by phononassisted non-radiative transitions between ortho (J ¼ 1) and optically forbidden para (J ¼ 0) excitons separated by 12 meV due to spin-orbit interaction. Thanks to the small radius, the exciton gas saturation density n s ¼ 10 20 cm À3 is much higher than the critical density n c ¼ 10 17 cm À3 needed for the quadrupole exciton BEC at T ¼ 2 K.Unfortunately, BEC turned out to be an elusive goal due to a strong recombination process that becomes effective at gas densities above %10 14 cm À3 . Usually, this undesirable

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Coulomb Correlations and Biexciton Signatures in Coherent Excitation Spectroscopy of Semiconductor Quantum Wells

Cited by 15 publications

References 29 publications

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

Polarization-dependent optical 2D Fourier transform spectroscopy of semiconductors

Polarization and wave-vector-dependent measurements by four-wave mixing in ZnO: valence-band ordering and biexcitons

Coherent manipulation of quadrupole biexcitons in cuprous oxide by 2D femtosecond spectroscopy

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