First-principles calculations and Raman scattering evidence for local symmetry lowering in rhombohedral ilmenite: temperature- and pressure-dependent studies

Autor(es)

Rodrigues, J. E. ^[1] ; Ferrer, M. M. ^[2] ; Cunha, T. R. ^[1] ; Costa, R. C. ^[3] ; Sambrano, J. R. ^[2] ; Rodrigues, A. D. ^[1] ; Pizani, P. S. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Opt Spect & Raman Scattering Res Grp, BR-13565905 Sao Carlos, SP - Brazil

^[2] Sao Paulo State Univ, Modeling & Mol Simulat Res Grp, UNESP, BR-17033360 Bauru, SP - Brazil

^[3] Univ Fed Campina Grande, Dept Environm Engn, BR-58840000 Pombal, PB - Brazil

• Tipo de documento: Artigo Científico
• Fonte: JOURNAL OF PHYSICS-CONDENSED MATTER; v. 30, n. 48 DEC 5 2018.
• Citações Web of Science: 3

Resumo

ATiO(3)-type materials may exist in two different crystalline forms: the perovskite and ilmenite. While many papers have devoted their attention to evaluating the structural properties of the perovskite phase, the structural stability of the ilmenite one still remains unsolved. Here, we present our results based on the lattice dynamics and first-principles calculations (density functional theory) of the CdTiO3 ilmenite phase, which are confronted with experimental data obtained through micro Raman spectroscopy that is a very good tool to probe the local crystal structure. Additional Raman bands, which are not foreseen from group-theory for the ilmenite rhombohedral structure, appeared in both low temperature (under vacuum condition) and high-pressure (at room temperature) spectra. The behavior can be explained by considering the local loss of inversion symmetry operation which reduces the overall space group from R (3) over bar (C-3i(2)) to R3 (C-3(4)). Our results can also be extended to other ilmenite-type compositions. (AU)

• Processo FAPESP: 13/07296-2 - CDMF - Centro de Desenvolvimento de Materiais Funcionais
• Beneficiário: Elson Longo da Silva
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 13/07793-6 - CEPIV - Centro de Ensino, Pesquisa e Inovação em Vidros
• Beneficiário: Edgar Dutra Zanotto
• Modalidade de apoio: Auxílio à Pesquisa - Centros de Pesquisa, Inovação e Difusão - CEPIDs
• Processo FAPESP: 16/07476-9 - Nanotubos porosos de carbono e de semicondutores inorgânicos: uma abordagem computacional
• Beneficiário: Julio Ricardo Sambrano
• Modalidade de apoio: Auxílio à Pesquisa - Regular