Temperature Dependence of Infrared-Active Phonons in CaTiO3: A Combined Spectroscopic and First-Principles Study

Published

January 21, 2002

Author(s)

V Zelezny, J Petzelt, M F. Limonov, D Usvyat, A A. Volkov, Eric J. Cockayne

Abstract

Spectroscopic studies involving dielectric, submillimeter, infrared and Raman measurements were performed on a CaTiO3 single crystal, covering a broad spectral range (static to 10 THz) at temperatures from 6 to 300 K. The results show mode softening characteristic of an incipient ferroelectric with Tc -100 K. A signature of the soft mode is seen in the Raman spectra, even though the soft modes are not Raman-active to first order. First-principles calculations were used to identify the phonons responsible for the spectral features. Many of the major features are due to phonons in orthorhombic CaTiO3 that are associated with zone-boundary phonons of the cubic perovskite phase.

Citation

Physical Review B (Condensed Matter and Materials Physics)

Volume

66

Pub Type

Journals

Keywords

Ab initio phonon calculations, calcium titanate, infrared reflectivity, infrared spectroscopy, Kramer-Kronig analysis, raman spectroscopy, soft mode behavior

Citation

Zelezny, V. , Petzelt, J. , Limonov, M. , Usvyat, D. , Volkov, A. and Cockayne, E. (2002), Temperature Dependence of Infrared-Active Phonons in CaTiO₃: A Combined Spectroscopic and First-Principles Study, Physical Review B (Condensed Matter and Materials Physics) (Accessed April 19, 2024)