Structural, electronic and optical properties of monoclinic Na2Ti3O7 from density functional theory calculations: a comparison with XRD and optical absorption measurements

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dc.creatorAdailton Azevedo Araújo Filho
dc.creatorFábio Lacerda Resende e Silva
dc.creatorAriete Righi
dc.creatorMauricélio Bezerra da Silva
dc.creatorBruno Poti e Silva
dc.creatorEwerton Wagner Santos Caetano
dc.creatorValder Nogueira Freire
dc.date.accessioned2023-06-27T18:08:50Z
dc.date.accessioned2025-09-09T00:37:44Z
dc.date.available2023-06-27T18:08:50Z
dc.date.issued2017
dc.description.sponsorshipCNPq - Conselho Nacional de Desenvolvimento Científico e Tecnológico
dc.description.sponsorshipINCT – Instituto nacional de ciência e tecnologia (Antigo Instituto do Milênio)
dc.identifier.doihttps://doi.org/10.1016/j.jssc.2017.03.017
dc.identifier.issn1095-726X
dc.identifier.urihttps://hdl.handle.net/1843/55425
dc.languageeng
dc.publisherUniversidade Federal de Minas Gerais
dc.relation.ispartofJournal of Solid State Chemistry
dc.rightsAcesso Restrito
dc.subjectPropriedades ópticas
dc.subjectRaios X
dc.subjectDifração
dc.subjectMicroscopia eletrônica de varredura
dc.subject.otherSodium trititanate
dc.subject.otherStructural properties
dc.subject.otherOptoelectronic properties
dc.subject.otherDFT calculations
dc.subject.otherX-ray diffraction
dc.subject.otherScanning electron microscopy
dc.subject.otherUV–VIS spectroscopy
dc.titleStructural, electronic and optical properties of monoclinic Na2Ti3O7 from density functional theory calculations: a comparison with XRD and optical absorption measurements
dc.typeArtigo de periódico
local.citation.epage74
local.citation.spage68
local.citation.volume250
local.description.resumoPowder samples of bulk monoclinic sodium trititanate Na2Ti3O7 were prepared carefully by solid state reaction, and its monoclinic P21/m crystal structure and morphology were characterized by X-ray powder diffraction (XRD) and scanning electron microscopy (SEM), respectively. Moreover, the sodium trititanate main energy band gap was estimated as Eg=3.51±0.01 eV employing UV–Vis spectroscopy, which is smaller than the measured 3.70 eV energy gap published previously by other authors. Aiming to achieve a better understanding of the experimental data, density functional theory (DFT) computations were performed within the local density and generalized gradient approximations (LDA and GGA, respectively) taking into account dispersion effects through the scheme of Tkatchenko and Scheffler (GGA+TS). Optimal lattice parameters, with deviations relative to measurements Δa=−0.06 Å, Δb=0.02 Å, and Δc=−0.09 Å, were obtained at the GGA level, which was then used to simulate the sodium trititanate electronic and optical properties. Indirect band transitions have led to a theoretical gap energy value of about 3.25 eV. Our results, however, differ from pioneer DFT results with respect to the specific Brillouin zone vectors for which the indirect transition with smallest energy value occurs. Effective masses for electrons and holes were also estimated along a set of directions in reciprocal space. Lastly, our calculations revealed a relatively large degree of optical isotropy for the Na2Ti3O7 optical absorption and complex dielectric function.
local.identifier.orcidhttps://orcid.org/0000-0002-8790-3944
local.identifier.orcidhttps://orcid.org/0000-0001-9719-4734
local.identifier.orcidhttps://orcid.org/0000-0001-8752-9609
local.identifier.orcidhttps://orcid.org/0000-0001-7941-3956
local.identifier.orcidhttps://orcid.org/0000-0001-5830-8903
local.identifier.orcidhttps://orcid.org/0000-0002-1021-6927
local.identifier.orcidhttps://orcid.org/0000-0001-7867-3908
local.publisher.countryBrasil
local.publisher.departmentICX - DEPARTAMENTO DE FÍSICA
local.publisher.initialsUFMG
local.url.externahttps://www.sciencedirect.com/science/article/pii/S0022459617300889

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