Screening by composite charged particles: the case of quantum well trions
Résumé
We study the screening of an external potentialproduced by a two-dimensional gas of charged excitons (trions). Wedetermine the contribution to the dielectric function induced bythese composite charged particles within a random phaseapproximation. In mixtures of free electrons and trions, the trionresponse is found dominant. In the long wave-length limit, trionsbehave as point charges with mass equal to the sum of the threeparticle components. For finite wave-vectors, we show how thedielectric response is sensitive to the composite nature of trionsand the internal degrees of freedom. Predictions are presentedfor the screening of a Coulomb potential, the scattering bycharged impurities and the properties of trionic plasmons.
Domaines
Autre [cond-mat.other]
Loading...