Resumo

SERRANO ALFARO, Pablo  e  ESTEVEZ-RAMS, Ernesto. Determination of close packed polytype sequence by computational simulation. Rev cuba cienc informat [online]. 2016, vol.10, suppl.1, pp. 17-26. ISSN 2227-1899.

ABSTRACT We aim at producing the close packed polytype sequence (CPs), based on information contained in the x-ray diffraction pattern. This problem has previously been addressed analytically (Estevez and Azanza, 2014), and its solution is intractable for real sequences. We use optimization algorithm based on meta-heuristic procedures, simulated annealing. The probability correlation functions, which can be extracted from the aforementioned diffraction pattern in polycrystalline samples, was taken as input to the problem. To reduce the computational complexity of the problem a number of consideration are taken into account, from areas such as theoretical crystallography and high-performance computing (polytypes generation). Important quantities are reviewed, as, the correlation length and the correlation matrix. We have validated the results obtained using synthetic sequences generated in a wide range of types, and proportion of planar defects. Partial results are shown, with emphasis on some types of close packed structures widely known such as: fcc, hcp and dhcp.

Palavras-chave : close packed; simulated annealing; correlation function; correlation length; polytypes.

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