Eur. Phys. J. B 22, 17-29 (2001)
https://doi.org/10.1007/PL00011131

Electron-hole diagrams versus exciton diagrams: the simplest problem on interacting excitons

GPS, Université Denis Diderot et Université Pierre et Marie Curie, CNRS, Tour 23, 2 place Jussieu, 75251 Paris Cedex 05, France

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

Received: 26 February 2001
Published online: 15 July 2001

Abstract

We study the interaction of an exciton with a distant metal, which is the simplest problem on interacting excitons: The semiconductor and metal electrons being "different" species, we do not have to worry about the tricky consequences of Pauli exclusion between identical carriers, which appear in any other problem on interacting excitons. We show how the exciton absorption, in the presence of semiconductor-metal interaction, can be derived in a very simple and transparent way from an exciton diagram procedure, provided that we use the appropriate exciton-metal interaction vertex, which contains the scattering from an exciton state to another exciton state under a Coulomb excitation. We also show that the resolution of this problem using standard electron-hole diagrams is dreadfully complicated at the lowest order in the semiconductor-metal interaction already, preventing a full calculation of the exciton-metal coupling from this usual technique.