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First-principles calculations of the phase stability of TiO2

Joseph Muscat, Varghese Swamy, Nicholas M. Harrison

Article (2002)

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Abstract

First-principles calculations of the crystal structures, bulk moduli, and relative stabilities of seven known andhypothetical TiO2 polymorphs ~anatase, rutile, columbite, baddeleyite, cotunnite, pyrite, and fluorite structures!have been carried out with the all-electron linear combination of atomic orbitals ~LCAO! and pseudopotentialplanewave ~PW! methods. The anatase versus rutile relative phase stability at 0 K and zero pressure has beeninvestigated using high-quality basis sets and carefully controlled computational parameters. From the optimalcrystal structures obtained with the Hartree-Fock theory at various pressures, the bulk modulus and phasetransition pressures of various high-pressure polymorphs have been derived at the athermal limit. In mostcases, the calculated unit cell data agree to within 2% of the corresponding experimental determination.Complete predicted structural data ~unit cell constants and fractional atomic coordinates! are presented for thebaddeleyite and pyrite forms. The calculated bulk moduli are within 10% of the most reliable experimentalresults. Both the all-electron LCAO and pseudopotential PW methods predict anatase to be more stable thanrutile at 0 K and ambient pressure. The computed anatase-columbite, rutile-columbite, columbite-baddeleyite,and baddeleyite-cotunnite phase transitions appear in the same order as observed in experiments, and thetransition pressures agree semiquantitatively with those measured. The pyrite and fluorite structures are predictedto be less stable than other polymorphs at pressures below 70 GPa in agreement with experiments.Finally, the elastic properties, compressibilities and phase transformations of the various polymorphs arediscussed in terms of simple models based on the behavior of the constituent Ti-O polyhedra under compression.
Subjects: 1800 Chemical engineering > 1800 Chemical engineering
1800 Chemical engineering > 1808 Rheology and processing
Department: Department of Chemical Engineering
Research Center: CRCT - Centre for Research in Computational Thermochemistry
Funders: EPSRC
PolyPublie URL: https://publications.polymtl.ca/5041/
Journal Title: Physical Review B (vol. 65, no. 22)
Publisher: APS Physics
DOI: 10.1103/physrevb.65.224112
Official URL: https://doi.org/10.1103/physrevb.65.224112
Date Deposited: 11 Sep 2020 14:25
Last Modified: 11 Nov 2022 14:19
Cite in APA 7: Muscat, J., Swamy, V., & Harrison, N. M. (2002). First-principles calculations of the phase stability of TiO2. Physical Review B, 65(22). https://doi.org/10.1103/physrevb.65.224112

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