Broad Doublet and Partially Softened Acoustic Mode in SrTiO₃

Abstract

The 90° light scattering experiment has been performed in a SrTi(¹⁸O_0.99 ¹⁶O_0.01)₃ (STO18-99) single crystal. The frequency shift and line width for each of three transverse acoustic modes c ₄₄, c ₅₅, and c ₆₆ modes) are precisely measured. From the data for these modes, the anisotropic feature of the broad doublet reported in SrTi¹⁶O₃ is discussed.

Keywords:

• SrTi¹⁸O₃
• broad doublet
• acoustic modes
• quantum paraelectrics
• light scattering

Acknowledgments

The authors express their appreciation to Mr. Yasushi Hirata and Mr. Tatsuji Meike for their continual improvement of the sample cell. The present work has been supported in part by a Grant-in-Aid for Scientific Research (C) from the Ministry of Education, Science, Sports and Culture of Japan, No. 17540287.