---
_id: '10827'
abstract:
- lang: eng
text: Titanium dioxide has been extensively studied in the rutile or anatase phase,
while its high-pressure phases are less well-understood, despite that many are
thought to have interesting optical, mechanical, and electrochemical properties.
First-principles methods, such as density functional theory (DFT), are often used
to compute the enthalpies of TiO2 phases at 0 K, but they are expensive and, thus,
impractical for long time scale and large system-size simulations at finite temperatures.
On the other hand, cheap empirical potentials fail to capture the relative stabilities
of various polymorphs. To model the thermodynamic behaviors of ambient and high-pressure
phases of TiO2, we design an empirical model as a baseline and then train a machine
learning potential based on the difference between the DFT data and the empirical
model. This so-called Δ-learning potential contains long-range electrostatic interactions
and predicts the 0 K enthalpies of stable TiO2 phases that are in good agreement
with DFT. We construct a pressure–temperature phase diagram of TiO2 in the range
0 < P < 70 GPa and 100 < T < 1500 K. We then simulate dynamic phase transition
processes by compressing anatase at different temperatures. At 300 K, we predominantly
observe an anatase-to-baddeleyite transformation at about 20 GPa via a martensitic
two-step mechanism with a highly ordered and collective atomic motion. At 2000
K, anatase can transform into cotunnite around 45–55 GPa in a thermally activated
and probabilistic manner, accompanied by diffusive movement of oxygen atoms. The
pressures computed for these transitions show good agreement with experiments.
Our results shed light on how to synthesize and stabilize high-pressure TiO2 phases,
and our method is generally applicable to other functional materials with multiple
polymorphs.
acknowledgement: J.G.L. and B.C. acknowledge the resources provided by the Cambridge
Tier-2 system operated by the University of Cambridge Research Computing Service
funded by the EPSRC Tier-2 capital (Grant No. EP/P020259/1).
article_number: '074106'
article_processing_charge: No
article_type: original
author:
- first_name: Jacob G.
full_name: Lee, Jacob G.
last_name: Lee
- first_name: Chris J.
full_name: Pickard, Chris J.
last_name: Pickard
- first_name: Bingqing
full_name: Cheng, Bingqing
id: cbe3cda4-d82c-11eb-8dc7-8ff94289fcc9
last_name: Cheng
orcid: 0000-0002-3584-9632
citation:
ama: Lee JG, Pickard CJ, Cheng B. High-pressure phase behaviors of titanium dioxide
revealed by a Δ-learning potential. The Journal of chemical physics. 2022;156(7).
doi:10.1063/5.0079844
apa: Lee, J. G., Pickard, C. J., & Cheng, B. (2022). High-pressure phase behaviors
of titanium dioxide revealed by a Δ-learning potential. The Journal of Chemical
Physics. AIP Publishing. https://doi.org/10.1063/5.0079844
chicago: Lee, Jacob G., Chris J. Pickard, and Bingqing Cheng. “High-Pressure Phase
Behaviors of Titanium Dioxide Revealed by a Δ-Learning Potential.” The Journal
of Chemical Physics. AIP Publishing, 2022. https://doi.org/10.1063/5.0079844.
ieee: J. G. Lee, C. J. Pickard, and B. Cheng, “High-pressure phase behaviors of
titanium dioxide revealed by a Δ-learning potential,” The Journal of chemical
physics, vol. 156, no. 7. AIP Publishing, 2022.
ista: Lee JG, Pickard CJ, Cheng B. 2022. High-pressure phase behaviors of titanium
dioxide revealed by a Δ-learning potential. The Journal of chemical physics. 156(7),
074106.
mla: Lee, Jacob G., et al. “High-Pressure Phase Behaviors of Titanium Dioxide Revealed
by a Δ-Learning Potential.” The Journal of Chemical Physics, vol. 156,
no. 7, 074106, AIP Publishing, 2022, doi:10.1063/5.0079844.
short: J.G. Lee, C.J. Pickard, B. Cheng, The Journal of Chemical Physics 156 (2022).
date_created: 2022-03-06T23:01:53Z
date_published: 2022-02-16T00:00:00Z
date_updated: 2023-08-02T14:45:46Z
day: '16'
department:
- _id: BiCh
doi: 10.1063/5.0079844
external_id:
arxiv:
- '2111.12968'
isi:
- '000796704500014'
intvolume: ' 156'
isi: 1
issue: '7'
language:
- iso: eng
main_file_link:
- open_access: '1'
url: https://arxiv.org/abs/2111.12968
month: '02'
oa: 1
oa_version: Preprint
publication: The Journal of chemical physics
publication_identifier:
eissn:
- '10897690'
publication_status: published
publisher: AIP Publishing
quality_controlled: '1'
scopus_import: '1'
status: public
title: High-pressure phase behaviors of titanium dioxide revealed by a Δ-learning
potential
type: journal_article
user_id: 4359f0d1-fa6c-11eb-b949-802e58b17ae8
volume: 156
year: '2022'
...