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Keywords:

  • Disordered semiconductor heterostructures;
  • excitons;
  • localizations;
  • Fano-coupling.

Abstract

Localization of the center-of-mass (com) motion of an exciton in a disordered semiconductor structure is studied theoretically by focusing on nonlinear optical spectroscopy. A one-dimensional tight-binding model with diagonal disorder is applied and the Coulomb interaction is treated consistently. In the ordered situation the center-of-mass momentum (K) selection rule leads to only the lowest transition for K = 0. The break down of the com-K-selection rule produces the well known asymmetric excitonic lines of disordered semiconductors. The coupling between the lowest dominant transition to this modified com-continuum yields Fano-like features in the nonlinear spectra.