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A first principles lattice dynamics and Raman spectra of the ferroelastic rutile to CaCl 2 phase transition in SnO 2 at high pressure
Author(s) -
Gupta Sanjay D.,
Gupta Sanjeev K.,
Jha Prafulla K.,
Ovsyuk N. N.
Publication year - 2013
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.4277
Subject(s) - raman spectroscopy , phonon , phase transition , rutile , raman scattering , condensed matter physics , ambient pressure , softening , lattice (music) , chemistry , materials science , thermodynamics , optics , physics , organic chemistry , acoustics , composite material
A first principles calculation of the lattice dynamical properties of rutile SnO 2 has been performed using density functional perturbation theory at ambient and high‐pressure conditions to understand the pressure‐induced phase transition. The calculated zone centre phonon modes at ambient and high pressures have been compared with Raman scattering and infrared measurements. Full phonon dispersion curves and phonon densities of states and Raman intensities at high pressures are calculated and given for the first time in literature. The ferroelastic transition from the rutile to the CaCl 2 ‐type structure was confirmed. It is clearly illustrated that the first transition is associated with macroscopic shear instability which arises from the strong coupling between elastic constants and softening of Raman active B 1g mode. The observed pressure of phase transition in experimental measurements was reproduced more accurately than in previous calculations, and the difference between observed and calculated transition pressure is only of the order of 2%. The mode Grüneisen parameter is quantitatively as well as qualitatively different from the earlier reported values. Copyright © 2013 John Wiley & Sons, Ltd.