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Electronic structure and absorption of semiconductor trion and biexciton - Sean Shiau - Mardi 24 mai 2016 à 11 h

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Sean Shiau -Départment de Physique, National Cheng Kung University, Tainan City , Taiwan

Actuellement chercheur invité CNRS pour 3 mois dans l’équipe Nanostructures et systèmes quantiques

Abstract

We approach the Schrodinger equation for trion and biexciton through the electron-exciton and two-exciton bases, respectively, using the composite boson many-body formalism, which allows an exact handling of fermion exchange. We numerically solve the resulting Schrodinger equations with the exciton relative motion states restricted to the lowest few states. The trion and biexciton ground-state energies obtained as a function of the electron-to-hole mass ratio are in reasonable agreement with those obtained through the best variational methods using free carriers. Compared with previous methods, the coboson many-body formalism allows us to reach bound and unbound excited states of trion and biexciton as easily as the ground state. Through their wave functions, we also obtain the optical absorption spectrum in the presence of hot carriers or exciton condensates for 2D quantum wells. We find large peaks located at the exciton levels, which are attributed to scattering states, and small peaks identified with trion and biexciton bound states.