<  Back to the Polytechnique Montréal portal

First-principles calculations of the phase stability of TiO2

Joseph Muscat, Varghese Swamy and Nicholas M. Harrison

Article (2002)

Open Acess document in PolyPublie and at official publisher
[img]
Preview
Open Access to the full text of this document
Published Version
Terms of Use: All rights reserved
Download (755kB)
Show abstract
Hide abstract

Abstract

First-principles calculations of the crystal structures, bulk moduli, and relative stabilities of seven known and hypothetical 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 pseudopotential planewave ~PW! methods. The anatase versus rutile relative phase stability at 0 K and zero pressure has been investigated using high-quality basis sets and carefully controlled computational parameters. From the optimal crystal structures obtained with the Hartree-Fock theory at various pressures, the bulk modulus and phase transition pressures of various high-pressure polymorphs have been derived at the athermal limit. In most cases, 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 the baddeleyite and pyrite forms. The calculated bulk moduli are within 10% of the most reliable experimental results. Both the all-electron LCAO and pseudopotential PW methods predict anatase to be more stable than rutile 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 the transition pressures agree semiquantitatively with those measured. The pyrite and fluorite structures are predicted to 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 are discussed 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: 05 Apr 2024 13:41
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

Statistics

Total downloads

Downloads per month in the last year

Origin of downloads

Dimensions

Repository Staff Only

View Item View Item