Antiferroelectric, Nonmetal, Optical properties, Trigonal

• Bi-Fe-O
• Bi-Na-O-Ti
• Ba-O-Ti
• B-Ge-La-O
• Bi-Fe-O-Y
• phonons
• Raman spectra
• wavenumber of optical phonon
• optical spectra
• luminescence
• nonmetal
• chalcogen
• antiferroelectric
• transitional
• ferroelectric