Dynamical exchange effects in a two-dimensional many-polaron gas
TFVS, Universiteit Antwerpen, Universiteitsplein 1, B2610
Corresponding author: a email@example.com
Published online: 9 April 2004
We calculate the influence of dynamical exchange effects on the response properties and the static properties of a two-dimensional many-polaron gas. These effects are not manifested in the random-phase approximation which is widely used in the analysis of the many-polaron system. Here they are taken into account by using a dielectric function derived in the time-dependent Hartree-Fock formalism. At weak electron-phonon coupling, we find that dynamical exchange effects lead to substantial corrections to the random-phase approximation results for the ground state energy, the effective mass, and the optical conductivity of the polaron system. Furthermore, we show that the reduction of the spectral weight of the optical absorption spectrum at frequencies above the longitudinal optical phonon frequency, due to many-body effects, is overestimated by the random-phase approximation.
PACS: 71.45.Gm – Exchange, correlation, dielectric and magnetic response functions, plasmons / 71.10.Pm – Fermions in reduced dimensions (anyons, composite fermions, Luttinger liquid, etc.) / 71.38.Fp – Large or Fröhlich polarons
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2004