[19p-W833-1~5] 9.1 Dielectrics, ferroelectrics

△ [19p-W833-3] Absorption Spectra at Terahertz Frequencies in YAlO₃

〇Yasuhiro Kuroda¹, Takaaki Morimoto¹, Yoshimichi Ohki^1,2 (1.Waseda Univ., 2.RIMST)

Keywords:YAlO3,terahertz wave,lattice vibration

A sharp absorption peak, probably due to lattice vibrations, appears at 3.75 THz in orthorhombic perovskite yttrium aluminate when the angle between its [001] direction and the direction of electric field of THz wave is 45°. It is known that the frequency of a similar absorption peak increases with an increase in interatomic distance between two rare-earth atoms in rare-earth aluminates containing Al. It has also been reported that there are three infrared active modes between two rare-earth atoms and that the phonon density of states is high in the vicinity of rare-earth in orthorhombic perovskite rare-earth oxides. Therefore, the 3.75-THz absorption seems to relate to one of the three active modes.