title: Surface diffusion of Cr adatoms on Au(111) by quantum tunneling.
abstract: The low-temperature surface diffusion of isolated Cr adatoms on Au(111) has been determined using nonperturbing x rays. Changes in the x-ray magnetic circular dichroism spectral line shape together with Monte Carlo calculations demonstrate that adatom nucleation proceeds via quantum tunneling diffusion rather than over-barrier hopping for temperatures <40K. The jump rates are shown to be as much as 35 orders of magnitude higher than that expected for thermal over-barrier hopping at 10 K.
authors.affiliation: Laboratoire pour l'Utilisation du Rayonnement Electromagnétique, UMR 130 CNRS-Université Paris Sud, 91898 Orsay, France. philippe.ohresser@synchrotron-soleil.fr
authors.forename: P
authors.initials: P
authors.lastname: Ohresser
authors.forename: H
authors.initials: H
authors.lastname: Bulou
authors.forename: S S
authors.initials: SS
authors.lastname: Dhesi
authors.forename: C
authors.initials: C
authors.lastname: Boeglin
authors.forename: B
authors.initials: B
authors.lastname: Lazarovits
authors.forename: E
authors.initials: E
authors.lastname: Gaudry
authors.forename: I
authors.initials: I
authors.lastname: Chado
authors.forename: J
authors.initials: J
authors.lastname: Faerber
authors.forename: F
authors.initials: F
authors.lastname: Scheurer