Coherent generation and interference of excitons and biexcitons in GaAs/AlxGa1

Binding of biexcitons in GaAs/AlxGa1−Mizeikis1, Birkedal2, Langbein3 et al. 1997Phys. Rev. BSelf Cite18180View full textAdd to dashboardCite

“…12 E b xx in this case can be determined from the energy difference between the biexciton and exciton resonance enhancements in the TFWM spectrum, representing the third-order nonlinear susceptibility, or from the period of quantum beats in the TFWM signal decay. 7 The spectra of the linear optical density of all samples are shown in Fig. 1.…”

“…Nonlinear quantum beat spectroscopy provides a straightforward way to determine the biexciton binding energy from the period of exciton-biexciton beats in the TFWM signal. 7 In samples where inhomogeneous broadening of the HH exciton is similar to the biexciton binding energy, the modulation of the spectrally integrated TFWM signal due to quantum beats is somewhat suppressed; however, pronounced beating can still be observed if the TFWM signal is spectrally resolved and detected at the energy of the biexcitonic resonant enhancement. In Fig.…”

“…The biexciton binding is enhanced in MQWs and E xx b varies within the range 1.0-2.6 meV, depending on the well width and degree of localization. 2,7,12,19 When the quantum well width varies from 80 to 160 Å, the ratio between the biexciton and exciton binding energies has been found to be constant 2 as described by Eq. ͑1͒.…”

“…The exciton binding energies were obtained from linear optical measurements and calculations, while the biexciton binding energies were measured from exciton-biexciton quantum beats in transient four-wave-mixing ͑TFWM͒ experiments. 7 We show that the biexciton binding energy remains constant when the superlattice barriers become thinner, until an abrupt decrease to the bulk value that occurs at a certain critical barrier thickness. This sharp change in the binding energy is associated with the transition from quasi-two-dimensional biexcitons to bulk biexcitons and occurs when the superlattice miniband halfwidth exceeds the exciton binding energy in the isolated quantum well of the same thickness.…”

Influence of well-width fluctuations on the binding energy of excitons, charged excitons, and biexcitons inGaAs-based quantum wells

“…These systems show nontrivial Coulomb correlation effects leading to interesting optical and transport characteristics not seen in bulk materials. A strong increase of the binding energy of the excitonic complexes was found experimentally [1,2,3,4,5,6,7,8,9,10] with decreasing quantum well (QW) width and increasing magnetic field [11].…”