Theoretical analysis of the structural deformation in Mn-doped BaTiO 3 J.R. Sambrano a, * , E. Orhan b, * , M.F.C. Gurgel c , A.B. Campos b , M.S. Go ´es d , C.O. Paiva-Santos d , J.A. Varela b , E. Longo c a Laborato ´ rio de Simulac ¸a ˜ o Molecular, Depto. de Matema ´ tica, Unesp -Universidade Estadual Paulista, C.P. 473, 17033-360 Bauru, Brazil b Laborato ´ rio Interdisciplinar em Cera ˆ mica, Depto de Fı ´sico-Quı ´mica, Instituto de Quı ´mica, Unesp - Universidade Estadual Paulista, C.P. 355, 14800-900, Araraquara, Brazil c Laborato ´ rio Interdisciplinar de Eletroquı ´mica e Cera ˆ mica, Depto de Quı ´mica, Universidade Federal de Sa ˜ o Carlos, C.P. 676, Sa ˜ o Carlos 13565-905, SP, Brazil d Laborato ´ rio Computacional de Ana ´ lises Cristalogra ´ ficas e Cristalinas, Depto Fı ´sico-Quı ´mica, Instituto de Quı ´mica, Unesp - Universidade Estadual Paulista, C.P. 355, 14800-900, Araraquara, Brazil Received 18 November 2004; in final form 10 December 2004 Available online 8 January 2005 Abstract An alternative theoretical method to simulate the structural deformation induced by Mn-doping in BaTiO 3 is proposed. The peri- odic quantum-mechanical method is based on density functional theory at B3LYP level. The structural models were obtained from Rietveld refinement of the undoped and Mn doped BaTiO 3 X-ray diffraction data. This modelization gives access to the dopant general effect on the electronic structure. In fact, the influence of the doping element itself on the electronic configuration is barely local; therefore, it is not included in the simulation. The simplicity of the model makes it available for working within a wide range of materials. Ó 2004 Published by Elsevier B.V. 1. Introduction The ATiO 3 titanates perovskites (A = Pb, Ca, Sr and Ba) have attracted considerable attention in the last years because are interesting semiconductor materials [1–3] with active optical properties such as electrolumi- nescence and photoluminescence (PL) at low tempera- ture and thus may be used as new optoelectronic devices with superior performance [1,4–7]. Due to their high technological interest, titanates per- ovskites are also the focus of numerous theoretical–com- putational studies. Often based on ab initio calculations, they can provide important informations regarding the electronic and structural properties of solids and the interpretation of experimental data [8–10]. Jiang and co-workers [11] presented the different ferroelectric behaviors of ATiO 3 on the basis of theoretical and experimental techniques. Meyer et al. [12] have per- formed plane-wave calculations within density func- tional theory (DFT) using ultrasoft pseudopotentials for (0 0 1) surfaces of the cubic perovskite ATiO 3 com- pounds. Recently, Zhang et al. [13] have carried out a theoretical work based on first principles study of bulk barium titanate, in the core-level spectra, under scissor approximation (FLAPW-SAT) and they manage to ex- plain the optical properties. Ab initio studies of ATiO 3 compounds thus can be performed by different methods without many prob- lems and can explain satisfactorily the experimental 0009-2614/$ - see front matter Ó 2004 Published by Elsevier B.V. doi:10.1016/j.cplett.2004.12.084 * Corresponding authors. Fax: +55 143 103 6096 (J.R. Sambrano). E-mail addresses: sambrano@fc.unesp.br (J.R. Sambrano), emma- nuelle.orhan@liec.ufscar.br (E. Orhan). www.elsevier.com/locate/cplett Chemical Physics Letters 402 (2005) 491–496