Eur. Phys. J. B 23, 139-151 (2001)
https://doi.org/10.1007/s100510170061

The exciton dead layer revisited

¹ GPS, Université Denis Diderot and Université Pierre et Marie Curie, CNRS, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France
² Laboratoire de Physique Statistique, École Normale Supérieure, 24 rue Lhomond, 75231 Paris Cedex 05, France

Corresponding author: ^a combescot@gps.jussieu.fr

Received: 26 December 2000
Revised: 4 April 2001
Published online: 15 September 2001

Abstract

Although the exciton in a quantum well is not a rigid ball but distords when its center of mass gets close to a surface, it is mathematically possible to write the exciton energy change from its bulk value as an effective decrease of the well width in which the center of mass would freely move. In the large well limit, the exciton dead layer defined this way is related to the third order term in the expansion of the exciton energy as a function of the inverse well width. A quite precise calculation of this exciton energy is thus necessary to obtain this dead layer. We present a new calculation which relies on a Born-Oppenheimer procedure to decouple the relative motion of the e-h pair from its center of mass motion. This is associated to a quite precise calculation of the relative motion energy, based on our recent work on the exact envelope function for confined motion. We predict that the dead layer increases with the exciton total mass in contradiction with previous results.