Helium-3 spin-echo measurements of K/Cu(001) are presented, the diffusional surface dynamics of the system at low coverages and on picosecond time scales. Langevin molecular-dynamics simulations are used, together with a potential-energy surface derived from density functional theory calculations, to provide further understanding of the experimental data. An anisotropic potential with a corrugation of 35-64 meV and a friction parameter of 1/4.5 ps-1 are found to give a good fit to the data for the lower coverages with the adsorbate interactions modeled with a dipole-dipole repulsion. Additionally, at the highest coverage, θ=0.084, a component of motion is observed perpendicular to the surface, analogous to that recently found for Na/Cu(001).
Surface dynamics and friction of K/Cu(001) characterized by helium-3 spin-echo and density functional theory / H. Hedgeland, P.R. Kole, H.R. Davies, A.P. Jardine, G. Alexandrowicz, W. Allison, J. Ellis, G. Fratesi, G.P. Brivio. - In: PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS. - ISSN 1098-0121. - 80:12(2009 Sep 28), pp. 125426.1-125426.7. [10.1103/PhysRevB.80.125426]
Surface dynamics and friction of K/Cu(001) characterized by helium-3 spin-echo and density functional theory
G. FratesiPenultimo
;
2009
Abstract
Helium-3 spin-echo measurements of K/Cu(001) are presented, the diffusional surface dynamics of the system at low coverages and on picosecond time scales. Langevin molecular-dynamics simulations are used, together with a potential-energy surface derived from density functional theory calculations, to provide further understanding of the experimental data. An anisotropic potential with a corrugation of 35-64 meV and a friction parameter of 1/4.5 ps-1 are found to give a good fit to the data for the lower coverages with the adsorbate interactions modeled with a dipole-dipole repulsion. Additionally, at the highest coverage, θ=0.084, a component of motion is observed perpendicular to the surface, analogous to that recently found for Na/Cu(001).File | Dimensione | Formato | |
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