Radiative Renormalizations for Excitonic Molecules

The influence of the polariton effects on the internal structure of an excitonic molecule (xx) is examined by the solution of the new xx Schr\"odinger equation which includes the polariton effects self-consistently. In 3D (CuCl) the radiative renormalizations yield a nonparabolic xx dispersion with infinite effective xx mass at zero momentum; in quasi-2D (GaAs) they give rise to a "Mexican hat" structure in the xx dispersion at small momenta together with a considerable increase of both the xx binding energy εˣˣ and the inverse xx radiative lifetime Γˣˣ. In quasi-1D the influence of the polariton effects is so strong that the xx exists only as a broad resonance (εˣˣ~Γˣˣ).