title: Excitonic effects in core-excitation spectra of semiconductors
abstract: Core-electron excitation spectra are used widely for structural and chemical analysis of materials, but interpretation of the near-edge structure remains unsettled, especially for semiconductors. For the important Si L(2,3) edge, there are two mutually inconsistent interpretations, in terms of effective-mass excitons and in terms of Bloch conduction-band final states. We report ab initio calculations and show that neither interpretation is valid and that the near-edge structure is in fact dominated by short-range electron-hole interactions even though the only bound excitons are effective-mass-like.
authors.affiliation: Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 and and Solid State Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
authors.initials: R
authors.lastname: Buczko
authors.initials: G
authors.lastname: Duscher
authors.initials: SJ
authors.lastname: Pennycook
authors.initials: ST
authors.lastname: Pantelides