Why ferroelectricity? synchrotron radiation and ab initio answers
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| Format: | Artículo científico |
| Language: | en |
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Sociedad Mexicana de Física A.C.
2007
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| _version_ | 1876460716337135616 |
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| author | F. Espinosa |
| author_facet | F. Espinosa |
| contents | Why ferroelectricity? synchrotron radiation and ab initio answers F. Espinosa E. Macías A. Durán J. Siqueiros R. Olivera M. García L. Fuentes M.E. Fuentes Física, Astronomía y Matemáticas Ferroelectricity synchrotron radiation ab initio calculations An old question of solid state physics is being answered nowadays: the atomic-level understanding of ferroelectricity. Traditional ideasabout ferroelectric phenomena relate with softening of optical phonons at the Brillouin zone origin and with W-shaped Landau freeenergy functions. Last decade experimental (synchrotron radiation, neutrons) and quantum-theoretical (Cohen, Resta, Spaldin) contributionshave clarified detailed descriptions and explanations for atomic behavior leading to spontaneous polarization in perovskite and perovskiterelatedcrystal structures. Work being performed by our interdisciplinary group on ferroelectricity is presented. Perovskite and Aurivilliusferroelectric phases are obtained by different methods. Fine details on crystal structures are investigated by means of synchrotron radiation atStanford Synchrotron Radiation Laboratory. Electronic structures of considered phases are theoretically characterized by ab initio methods.High-resolution diffraction experiments demonstrate several symmetry break-downs in perovskite and Aurivillius phases. The structuresymmetry-polarization relationship is discussed for a number of representative cases. Ab initio explanation of ferroelectric polarization inperovskite structures is given. Energy calculation is performed by means of CASTEP code under GGA functional. Energy optimization leadsto cubic-tetragonal symmetry break-down with off-centering cation displacements via second-order Jahn-Teller effect. Electronic structureis investigated with BandLab code, under LDA functional with LMTO method. Degeneracy of Ti 3d z2 and Ti 3d (x2+y2) orbitals is thecause of cubic-perovskite deformation. 2007 artículo científico 0035-001X https://www.redalyc.org/articulo.oa?id=57066324 https://www.redalyc.org/journal/570/57066324/ https://www.redalyc.org/journal/570/57066324/html/ https://www.redalyc.org/journal/570/57066324/57066324.epub https://www.redalyc.org/journal/570/57066324/movil en http://www.redalyc.org/revista.oa?id=570 Revista Mexicana de Física application/pdf Sociedad Mexicana de Física A.C. Revista Mexicana de Física (México) Num.3 Vol.53 |
| format | Artículo científico |
| id | redalyc_57066324 |
| institution | Redalyc |
| language | en |
| publishDate | 2007 |
| publisher | Sociedad Mexicana de Física A.C. |
| spellingShingle | Why ferroelectricity? synchrotron radiation and ab initio answers F. Espinosa Física, Astronomía y Matemáticas Ferroelectricity synchrotron radiation ab initio calculations Why ferroelectricity? synchrotron radiation and ab initio answers F. Espinosa E. Macías A. Durán J. Siqueiros R. Olivera M. García L. Fuentes M.E. Fuentes Física, Astronomía y Matemáticas Ferroelectricity synchrotron radiation ab initio calculations An old question of solid state physics is being answered nowadays: the atomic-level understanding of ferroelectricity. Traditional ideasabout ferroelectric phenomena relate with softening of optical phonons at the Brillouin zone origin and with W-shaped Landau freeenergy functions. Last decade experimental (synchrotron radiation, neutrons) and quantum-theoretical (Cohen, Resta, Spaldin) contributionshave clarified detailed descriptions and explanations for atomic behavior leading to spontaneous polarization in perovskite and perovskiterelatedcrystal structures. Work being performed by our interdisciplinary group on ferroelectricity is presented. Perovskite and Aurivilliusferroelectric phases are obtained by different methods. Fine details on crystal structures are investigated by means of synchrotron radiation atStanford Synchrotron Radiation Laboratory. Electronic structures of considered phases are theoretically characterized by ab initio methods.High-resolution diffraction experiments demonstrate several symmetry break-downs in perovskite and Aurivillius phases. The structuresymmetry-polarization relationship is discussed for a number of representative cases. Ab initio explanation of ferroelectric polarization inperovskite structures is given. Energy calculation is performed by means of CASTEP code under GGA functional. Energy optimization leadsto cubic-tetragonal symmetry break-down with off-centering cation displacements via second-order Jahn-Teller effect. Electronic structureis investigated with BandLab code, under LDA functional with LMTO method. Degeneracy of Ti 3d z2 and Ti 3d (x2+y2) orbitals is thecause of cubic-perovskite deformation. 2007 artículo científico 0035-001X https://www.redalyc.org/articulo.oa?id=57066324 https://www.redalyc.org/journal/570/57066324/ https://www.redalyc.org/journal/570/57066324/html/ https://www.redalyc.org/journal/570/57066324/57066324.epub https://www.redalyc.org/journal/570/57066324/movil en http://www.redalyc.org/revista.oa?id=570 Revista Mexicana de Física application/pdf Sociedad Mexicana de Física A.C. Revista Mexicana de Física (México) Num.3 Vol.53 |
| title | Why ferroelectricity? synchrotron radiation and ab initio answers |
| topic | Física, Astronomía y Matemáticas Ferroelectricity synchrotron radiation ab initio calculations |
| url | https://www.redalyc.org/articulo.oa?id=57066324 https://www.redalyc.org/journal/570/57066324/ https://www.redalyc.org/journal/570/57066324/html/ https://www.redalyc.org/journal/570/57066324/57066324.epub https://www.redalyc.org/journal/570/57066324/movil |