title: Coherence during scattering of fast H atoms from a LiF(001) surface.
abstract: The coherence for diffraction effects during grazing scattering of fast hydrogen and helium atoms from a LiF(001) surface with energies up to some keV is investigated via the coincident detection of two-dimensional angular distributions for scattered projectiles with their energy loss. For keV H atoms, we identify electronic excitations of the target surface as the dominant mechanism for decoherence, whereas for He atoms this contribution is small. The suppression of electronic excitations owing to the band gap of insulators plays an essential role for preserving quantum coherence and thus for the application of fast atom diffraction as a surface analytical tool.
authors.affiliation: Institut für Physik, Humboldt Universität zu Berlin, Brook-Taylor-Straße 6, D-12489 Berlin-Adlershof, Germany.
authors.forename: J
authors.initials: J
authors.lastname: Lienemann
authors.forename: A
authors.initials: A
authors.lastname: Schüller
authors.forename: D
authors.initials: D
authors.lastname: Blauth
authors.forename: J
authors.initials: J
authors.lastname: Seifert
authors.forename: S
authors.initials: S
authors.lastname: Wethekam
authors.forename: M
authors.initials: M
authors.lastname: Busch
authors.forename: K
authors.initials: K
authors.lastname: Maass
authors.forename: H
authors.initials: H
authors.lastname: Winter