Adatom diffusion on a square lattice. Theoretical and numerical studies |
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Authors: | AA Tarasenko F Nieto L Jastrabík C Uebing |
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Institution: | Institute of Physics, National Academy of Sciences of Ukraine Prospect Nauki 46, 252028, Kyiv 28, Ukraine, UA Departamento de Física and Centro Latinoamericano de Estudios Ilya Prigogine, Universidad Nacional de San Luis, CONICET, Chacabuco 917, 5700 San Luis, Argentina, AR Institute of Physics, Academy of Sciences of the Czech Republic Na Slovance 2, 180 40 Praha 8, Czech Republic, CZ Max-Planck-Institut für Eisenforschung, Max-Planck Strasse 1, 40074 Düsseldorf, Germany, DE
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Abstract: | A two-dimensional lattice-gas model with square symmetry is investigated by using the real-space renormalization group (RSRG)
approach with blocks of different size and symmetries. It has been shown that the precision of the method depends strongly
not only on the number of sites in the block but also on its symmetry. In general, the accuracy of the method increases with
the number of sites in the block. The minimal relative error in determining the critical values of the interaction parameters
is equal to . Using the RSRG method, we have explored phase diagrams of both a two-dimensional Ising spin model and of a square lattice
gas with lateral interactions between adparticles. We also have investigated the influence of the attractive and repulsive
interactions on both the thermodynamic properties of the lattice gas and the diffusion of adsorbed particles over surface.
We have calculated adsorption isotherms and coverage dependences of the pair correlation function, isothermal susceptibility
and the chemical diffusion coefficient. In addition, we have included in our analysis the interaction of the activated particle
in the saddle point with its nearest neighbors. We have also used Monte Carlo (MC) technique to calculate these dependences.
Despite the fact that both methods constitute very different approaches, the correspondence of the numerical data is surprisingly
good. Therefore, we conclude that the RSRG approach can be applied to characterize the thermodynamic and kinetic properties
of systems of particles with strong lateral interactions.
Received 1st September 1998 and Received in final form 8 March 2000 |
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Keywords: | PACS 64 60 Ak Renormalization-group fractal and percolation studies of phase transitions - 68 35 Rh Phase transitions and critical phenomena - 68 35 Fx Diffusion interface formation |
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