Surface diffusion of Cr adatoms on Au(111) by quantum tunneling.
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.
Ohresser
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P
Laboratoire pour l'Utilisation du Rayonnement Electromagnétique, UMR 130 CNRS-Université Paris Sud, 91898 Orsay, France. philippe.ohresser@synchrotron-soleil.fr
Bulou
H
H
Dhesi
S S
SS
Boeglin
C
C
Lazarovits
B
B
Gaudry
E
E
Chado
I
I
Faerber
J
J
Scheurer
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F