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https://hdl.handle.net/2115/14401

Perfect Softening of the Ferroelectric Mode in the Isotope-Exchanged Strontium Titanate of SrTi^18O3 Studied by Light Scattering

Perfect Softening of the Ferroelectric Mode in the Isotope-Exchanged Strontium Titanate of SrTi^{18}O_{3} Studied by Light Scattering

英語

Infrared and Raman spectra (condensed matter)

2006-06-09

American Physical Society

Physical Review Letters

96(22)

227602

The Eu mode of the isotope-induced ferroelectric strontium titanate SrTi^18O3 shows a perfect softening at the ferroelectric phase transition temperature Tc, where the frequency of the underdamped mode approaches completely to zero within the instrumental resolution. The spectra of the Raman inactive soft Eu mode have been successfully observed owing to local symmetry breaking and by long-term accumulation of the spectral intensity with a high resolution technique. The mechanism of the phase transition is concluded to be an ideal displacive-type accompanied with perfect softening of the Slater-type polar Eu mode. The difference between the soft mode behavior of SrTi^16O3 and SrTi^18O3 indicates that the origin of the quantum paraelectric state of SrTi^16O3 lies in the quantum fluctuation of the oxide octahedron in the perovskite structure.

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Copyright © 2006 The American Physical Society

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