Volume 107, Number 3, August 2014
|Number of page(s)||5|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||04 August 2014|
Pressure-induced antiferrodistortive phase transition in SrTiO3: Common scaling of soft-mode with pressure and temperature
1 Department of Physics, University of Illinois - 1110 West Green Street, Urbana, IL 61801-3080, USA
2 Frederick Seitz Materials Research Laboratory, University of Illinois - 104 South Goodwin Avenue, Urbana, IL 61801-2902, USA
3 National Synchrotron Radiation Research Center - Hsinchu 30076, Taiwan, Republic of China
4 Advanced Photon Source, Argonne National Laboratory - 9700 South Cass Avenue, Lemont, IL 60439, USA
5 Institute of Atomic and Molecular Science, Academia Sinica - Taipei, Taiwan, Republic of China
6 European Synchrotron Radiation Facility - Grenoble, France
Received: 26 March 2014
Accepted: 14 July 2014
We report a study of the pressure-induced antiferrodistortive cubic-to-tetragonal phase transition in strontium titanate (SrTiO3) at ambient temperature. High-resolution inelastic x-ray scattering measurements reveal the softening of a phonon mode at the zone boundary; a static distortion sets in at a critical pressure of 9.5 GPa, which corresponds to a critical volume reduction of 5.3%. Prior studies have shown that similar phonon softening and ensuing lattice distortion can be induced under ambient pressure by lowering the sample temperature through a critical temperature of 105 K. The relationship between the two phase transitions is clarified by comparing the power laws of the pressure and temperature dependences of the softening behavior. The results are explained in terms of the analytic properties of the soft mode.
PACS: 63.20.-e – Phonons in crystal lattices / 81.40.Vw – Pressure treatment / 78.70.Ck – X-ray scattering
© EPLA, 2014
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