Direct observation of the soft-mode dispersion in the incipient ferroelectric KTaO3

作     者：Yuki Ichikawa Masaya Nagai Koichiro Tanaka 

作者机构：Department of Physics Graduate School of Science Kyoto University Sakyo-ku Kyoto 606-8502 Japan Core Research for Evolutional Science and Technology (CREST) Japan Science and Technology Corporation Japan 

出 版 物：《Physical Review B》 (Phys. Rev. B Condens. Matter Mater. Phys.)

年 卷 期：2005年第71卷第9期

页      面：092106-092106页

核心收录：

学科分类：0808[工学-电气工程] 0809[工学-电子科学与技术（可授工学、理学学位）] 07[理学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0702[理学-物理学] 

摘      要：Far-infrared dispersion of the complex dielectric constant in incipient ferroelectric KTaO3 has been revealed by terahertz time-domain spectroscopy (THz-TDS) in the temperature range from 8K to 300K. The real part of the complex dielectric constant in the far-infrared region is larger than the static permittivity. Through the analysis using a single Lorentz oscillator model, we conclude that the origin of the extremely large static permittivity in KTaO3 and its anomalous behavior at low temperatures are almost fully attributed to the TO1 mode dispersion and the suppression of the softening.