We present the results of a comparative study of the equilibrium crystal structure and vibrational properties of the Na/Cu(111) adsorbed systems at coverages up to the monolayer saturation. The calculations are performed with interaction potentials from the embedded{atom method. The following ordered structures are considered: p(3*3), p(2*2), (¹3*¹3)30°, and (3/2*3/2). The surface relaxation, phonon dispersion, and polarization of vibrational modes for the adsorbate and substrate atoms as well as the local density of states are discussed. It is found that the bond length between an adsorbate and the nearest neighbor substrate atom slightly increases with increasing of coverage. Adsorption of sodium also results in a small rumpling in the two substrate layers. The mode associated with adatom substrate stretch vibrations was obtained in our calculation at about 22 meV for all the structures considered. The intensity of this mode decreases with increasing of coverage in accordance with the experiment
Borisova, S., Rusina, G., Eremeev, S., Benedek, G., Echenique, P., Sklyadneva, I., et al. (2006). Vibrations in submonolayer structures of Na on Cu(111). PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 74(16), 1-11 [10.1103/PhysRevB.74.165412].
Vibrations in submonolayer structures of Na on Cu(111)
BENEDEK, GIORGIO;
2006
Abstract
We present the results of a comparative study of the equilibrium crystal structure and vibrational properties of the Na/Cu(111) adsorbed systems at coverages up to the monolayer saturation. The calculations are performed with interaction potentials from the embedded{atom method. The following ordered structures are considered: p(3*3), p(2*2), (¹3*¹3)30°, and (3/2*3/2). The surface relaxation, phonon dispersion, and polarization of vibrational modes for the adsorbate and substrate atoms as well as the local density of states are discussed. It is found that the bond length between an adsorbate and the nearest neighbor substrate atom slightly increases with increasing of coverage. Adsorption of sodium also results in a small rumpling in the two substrate layers. The mode associated with adatom substrate stretch vibrations was obtained in our calculation at about 22 meV for all the structures considered. The intensity of this mode decreases with increasing of coverage in accordance with the experiment
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