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arXiv · 1002.4492

Fundamental collapse of the exciton-exciton effective scattering

Laura Pilozzi·Monique Combescot·Odile Betbeder-Matibet·Andrea D'Andrea
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Abstract

The exciton-exciton effective scattering which rules the time evolution of two excitons is studied as a function of initial momentum difference, scattering angle and electron-to-hole mass ratio. We show that this effective scattering can collapse for energy-conserving configurations provided that the difference between the two initial exciton momenta is larger than a threshold value. Sizeable scatterings then exist in the forward direction only. We even find that, for an electron-to-hole mass ratio close to 1/2, the exciton-exciton effective scattering stays close to zero in all directions when the difference between the initial exciton momenta has a very specific value. This unexpected but quite remarkable collapse comes from tricky compensation between direct and exchange Coulomb processes which originates from the fundamental undistinguishability of the exciton fermionic components.

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Laura Pilozzi, Monique Combescot, Odile Betbeder-Matibet, Andrea D'Andrea. 2010-02-24. Fundamental collapse of the exciton-exciton effective scattering. https://doi.org/10.1103/physrevb.82.075327

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