The electronic properties and lattice dynamics of (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3}: From cubic to tetragonal and rhombohedral phases

Journal Article · Fri Mar 28 00:00:00 EDT 2014 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4869733· OSTI ID:22271138

Lü, Hongfeng ^[1]; Wang, Shanying ^[2]; Wang, Xiaosu ^[1]

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1. Department of Applied Physics, College of Science, China Agricultural University, Beijing 100083 (China)
2. Department of Physics, Tsinghua University, Beijing 100084 (China)

The structural, electronic and dynamical properties of the cubic, tetragonal and rhombohedral phases of a lead-free ferroelectrics, (Na{sub 0.5}Bi{sub 0.5})TiO{sub 3} (NBT), have been studied with a density functional formalism. The direct band gap is determined to be 2∼3 eV for three phases, suggesting them to be good optical material. The equilibrium structures were given, and the importance of Bi atom in the low-symmetry ferroelectric phases were investigated with the electron localization functions analysis. The vibration modes at the Γ point were calculated to provide a basis for analyzing the Raman and IR spectra. Soft modes were found in both the cubic and the tetragonal phases, providing a clue in understanding the ferroelectric phase transition in NBT.

• OSTI ID: 22271138
• Journal Information: Journal of Applied Physics, Vol. 115, Issue 12; 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

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BISMUTH COMPOUNDS
CUBIC LATTICES
DENSITY FUNCTIONAL METHOD
ELECTRONIC STRUCTURE
ELECTRONS
ENERGY GAP
FERROELECTRIC MATERIALS
INFRARED SPECTRA
OSCILLATION MODES
PHASE TRANSFORMATIONS
RAMAN SPECTRA
SODIUM COMPOUNDS
TETRAGONAL LATTICES
TITANATES
TRIGONAL LATTICES