Title:
The local structure, electronic and optical properties of Pb(Mg1/3Nb2/3)O3-PbTiO3: first-principles study
Author(s):
M. Kovalenko
(Solid State Physics Department, Faculty of Physics, Ivan Franko National University of Lviv, 8, Kyrylo and Mefodiy Str., 79005 Lviv, Ukraine),
|
|
O. Bovgyra
(Solid State Physics Department, Faculty of Physics, Ivan Franko National University of Lviv, 8, Kyrylo and Mefodiy Str., 79005 Lviv, Ukraine),
|
|
V. Kapustianyk
(Solid State Physics Department, Faculty of Physics, Ivan Franko National University of Lviv, 8, Kyrylo and Mefodiy Str., 79005 Lviv, Ukraine),
|
|
O. Kozachenko
(Solid State Physics Department, Faculty of Physics, Ivan Franko National University of Lviv, 8, Kyrylo and Mefodiy Str., 79005 Lviv, Ukraine)
| |
Pb(Mg1/3Nb2/3)O3-PbTiO3 perovskite-based crystals attract considerable scientific interest due to their interes-ting properties and possible use in piezoelectricity and photovoltaics. To understand the local structure and fundamental properties of such materials, in this work, we focused on the study within the density functional theory of structural, electronic, and optical properties of Pb[(Mg1/3Nb2/3)0.75Ti0.25]O3. Using GGA(PBEsol) approximation for structure optimization gives good agreement with experimental data. Through the variation in Hubbard U parameters to GGA(PBEsol) functional, we achieve the bandgap for the Pb[(Mg1/3Nb2/3)0.75Ti0.25]O3 that is in good agreement with the experimental one. A study of the bond populations showed that the Mg-O bond demonstrates no covalency, whereas there is a significant Ti-O and Nb-O covalent bonding. Such different bon-ding characters must be responsible for the relaxor properties of Pb[(Mg1/3Nb2/3)0.75Ti0.25]O3 compound. In addition, the investigation of the optical properties of the Pb[(Mg1/3Nb2/3)0.75Ti0.25]O3 by adopting Hubbard U corrections, modifying the error of the GGA approximation, and confirming the electronic analysis were performed.
Key words: PMN-PT, local structure, bandgap, density of states, optical properties
| << List of papers |