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Optical phonon modes in 1:2 ordered trigonal Ba 3 MgNb 2 O 9 perovskite: Synergy of both classical and quantum methods
Author(s) -
Ferrer Mateus M.,
Sambrano Julio R.,
Hernandes Antonio C.,
Rodrigues João E. F. S.
Publication year - 2020
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.5895
Subject(s) - phonon , brillouin zone , density functional theory , raman spectroscopy , perovskite (structure) , dielectric , microwave , chemistry , condensed matter physics , materials science , computational chemistry , physics , optics , crystallography , quantum mechanics , optoelectronics
Abstract Ba 3 MgNb 2 O 9 is a double perovskite niobate with a trigonal structure with space group D 3 d 3 . Such a niobium‐based compound has a great potential for applications as microwave dielectrics in the telecommunication industry. In this work, we report the lattice dynamics calculation results using a Short‐Range Force Field Model and Density Functional Theory to represent the optical phonon modes at Γ‐point of the Brillouin zone. The classical method uses the nearest neighbor interactions through the interatomic force constants to describe the local order for Raman and infrared spectra. At the same time, density functional theory methods took into account two functionals ( PBE and B3LYP ) in order to provide the optical modes through second derivatives of the total energy. In both methods, theoretical optical modes are in good agreement with reported experimental data. The combination of both classical and quantum theoretical methods provided basis for a systematic discussion on the origin of the optical modes including the prediction of the dielectric tensor. We believe that this work presents useful information about the structural and vibrational characterization of Ba 3 MgNb 2 O 9 perovskite and possible targeting for its application as microwave dielectrics for the communication technology.