High pressure phase transitions in SnO2 polymorphs by first-principles calculations

The structural and mechanical properties of SnO2 polymorphs are investigated by the calculations of first-principles density functional theory (DFT) which employs Generalized Gradient Approximation (GGA) parameterized by Perdew-Burke-Ernzerhof (PBE). Structural parameters are in good agreement with experimental and other theoretical results. Pressure induced phase transitions have occurred in the following sequence: the rutile-type --> the CaCl2-type at 7.59 GPa, the CaCl2-type --> the alpha-PbO2-type at 11.50 GPa, the alpha-PbO2-type --> the pyrite-type at 18.70 GPa, the pyrite-type --> the ZrO2-type at 25.69 GPa, the ZrO2-type --> the cotunnite-type at 32.71 GPa, the cotunnite-type --> the fluorite-type at 19.70 GPa. The mechanical properties of these polymorphs such as bulk modulus B-0 and its first derivative B-0' and the elastic stiffness constants of them are calculated. It is shown that the results determined in this study are compatible with the experimental and other theoretical calculations. (C) 2013 Elsevier B.V. All rights reserved.