title: How Atomic Steps Modify Diffusion and Inter-adsorbate Forces: Empirical Evidence from Hopping Dynamics in Na/Cu(115).
abstract: We followed the collective atomic-scale motion of Na atoms on a vicinal Cu(115) surface within a time scale of pico- to nanoseconds using helium spin echo spectroscopy. The well-defined stepped structure of Cu(115) allows us to study the effect that atomic steps have on the adsorption properties, the rate for motion parallel and perpendicular to the step edge, and the interaction between the Na atoms. With the support of a molecular dynamics simulation we show that the Na atoms perform strongly anisotropic 1D hopping motion parallel to the step edges. Furthermore, we observe that the spatial and temporal correlations between the Na atoms that lead to collective motion are also anisotropic, suggesting the steps efficiently screen the lateral interaction between Na atoms residing on different terraces.
authors.affiliation: Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Technion City, Haifa 32000, Israel.
authors.forename: O
authors.initials: O
authors.lastname: Godsi
authors.affiliation: Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Technion City, Haifa 32000, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Corem
authors.affiliation: Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Technion City, Haifa 32000, Israel.
authors.forename: T
authors.initials: T
authors.lastname: Kravchuk
authors.affiliation: Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum , D-44780 Bochum, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Bertram
authors.affiliation: Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum , D-44780 Bochum, Germany.
authors.forename: K
authors.initials: K
authors.lastname: Morgenstern
authors.affiliation: The Cavendish Laboratory , J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: H
authors.initials: H
authors.lastname: Hedgeland
authors.affiliation: The Cavendish Laboratory , J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: A P
authors.initials: AP
authors.lastname: Jardine
authors.affiliation: The Cavendish Laboratory , J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: W
authors.initials: W
authors.lastname: Allison
authors.affiliation: The Cavendish Laboratory , J. J. Thomson Avenue, Cambridge CB3 0HE, United Kingdom.
authors.forename: J
authors.initials: J
authors.lastname: Ellis
authors.affiliation: Schulich Faculty of Chemistry, Technion - Israel Institute of Technology , Technion City, Haifa 32000, Israel.
authors.forename: G
authors.initials: G
authors.lastname: Alexandrowicz