Abstract
A study of soft modes in SrTiO3 using a temperature-derivative Raman technique is reported. The A1g component of the mode which softens towards the phase transition at 108 K has been studied below the phase-transition temperature. The energy of the modes as a function of temperature was followed down to 4 cm-1. The square of the energy of this mode deviates from the Landau behavior for TTc>0.95 and follows a temperature dependence very similar to that of the rotation of the octahedra in SrTiO3. The soft ferroelectric mode has been observed for the first time in second-order Raman. It is shown that two structures in the spectra correspond to a replica of the soft mode and to the simultaneous emission of the soft mode and the absorption of an acoustic mode close to the Γ point.
Original language | English |
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Pages (from-to) | 4132-4140 |
Number of pages | 9 |
Journal | Physical Review B |
Volume | 13 |
Issue number | 9 |
DOIs | |
State | Published - 1976 |