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Percolation picture for long wavelength phonons in zinc blende alloys: application to GaInAs

Percolation picture for long wavelength phonons in zinc blende alloys: application to GaInAs

O. Pagès, T. Tite, A. Chafi, J. Gleize, J.P. Laurenti, J. Hugel, A.V. Postnikov, E. Tournié, O. Maksimov M.C. Tamargo
Journal of Physics and Chemistry of Solids, Vol.66(11), pp.2094-2098
International Conference on Ternary and Multinary Compounds (ICTMC) 14 (Denver, United States, 2004)
11/2005
We propose a ‘one bond→two modes’ model for the long wavelength optical phonons in random zinc-blende AxB1−xC ternary alloys, based on the percolation site theory. Our model takes into account the ‘fractal→normal’ object transition, which goes with the ‘dispersion→continuum’ topology transition at the percolation thresholds of the A–C and B–C bonds. We first introduce the basics of our model in the case of Zn1−xBex(Se,Te) mixed crystals, whose parent binaries display a high contrast in the bond stiffness, which enhances the percolation effects. We then focus our study on standard systems, which display a much weaker contrast in the bond stiffness. The multi-phonon behavior of GaInAs alloys is re-examined in the light of the percolation model, with much success.

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