Resumo

MACHADO, R.; STACHIOTTI, M.G.; MIGONI, R.L.  e  HUANOSTA TERA, A.. Estructura electrónica y origen de la ferroelectricidad en el Bi₄Ti₃O₁₂, por medio de cálculos de primeros principios. Rev. mex. fis. [online]. 2005, vol.51, n.2, pp.186-192. ISSN 0035-001X.

Using the full-potential augmented plane-wave method (LAPW-method), theoretical results on the electronic structure and ferroelectric instabilities in the structure of Bi₄Ti₃O₁₂are presented here. The equilibrium coordinates of all the atoms in the tetragonal phase (paraelectric) were calculated. Using the frozen phonon method, it was found that in the considered crystalline structure there are two unstable phonon modes with different displacement patterns, which explain at least partially the primary source for ferroelectricity in the studied compound. Besides, the band structure, the total and site-projected electronic densities of states for the valence and conduction bands of Bi₄Ti₃O₁₂are reported, which allowed us to understand the electronic origin of the ferroelectric instabilities.

Palavras-chave : LAPW-method; ferroelectric instabilities; equilibrium coordiantes; phonon modes; band structure.

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