Structural, electronic, vibrational, and dielectric properties of LaBGeO{sub 5} from first principles
- Department of Physics, The University of Jordan, 11942 Amman (Jordan)
- Institute of Condensed Matter and Nanosciences (IMCN/NAPS), Université Catholique de Louvain (UCL), 8 Chemin des étoiles, B-1348 Louvain-la Neuve (Belgium)
Structural, electronic, vibrational, and dielectric properties of LaBGeO{sub 5} with the stillwellite structure are determined based on ab initio density functional theory. The theoretically relaxed structure is found to agree well with the existing experimental data with a deviation of less than 0.2%. Both the density of states and the electronic band structure are calculated, showing five distinct groups of valence bands. Furthermore, the Born effective charge, the dielectric permittivity tensors, and the vibrational frequencies at the center of the Brillouin zone are all obtained. Compared to existing model calculations, the vibrational frequencies are found in much better agreement with the published experimental infrared and Raman data, with absolute and relative rms values of 6.04 cm{sup −1}, and 1.81%, respectively. Consequently, numerical values for both the parallel and perpendicular components of the permittivity tensor are established as 3.55 and 3.71 (10.34 and 12.28), respectively, for the high-(low-)frequency limit.
- OSTI ID:
- 22278031
- Journal Information:
- Journal of Applied Physics, Vol. 115, Issue 7; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
First-principle calculation and assignment for vibrational spectra of Ba(Mg{sub 1/3}Nb{sub 2/3})O{sub 3} microwave dielectric ceramic
Correlations of dielectric properties with electronic structure and phonon vibration of low loss tunable Ba{sub 0.4}Sr{sub 0.6}Ti{sub 1-y}Mn{sub y}O{sub 3} ceramics