title: Wave-vector-dependent exciton exchange interaction.
abstract: The exchange interaction for the yellow 1S orthoexciton in Cu2O is derived up to the order K2. The resulting exchange splittings are verified experimentally using high resolution spectroscopy. In agreement with theory the fine structure shows a characteristic dependence on the direction of the wave vector.
authors.affiliation: Institut für Physik, Universität Dortmund, D-44221 Dortmund, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Dasbach
authors.forename: D
authors.initials: D
authors.lastname: Fröhlich
authors.forename: H
authors.initials: H
authors.lastname: Stolz
authors.forename: R
authors.initials: R
authors.lastname: Klieber
authors.forename: D
authors.initials: D
authors.lastname: Suter
authors.forename: M
authors.initials: M
authors.lastname: Bayer