Temperature-dependent microstructural evolution of hexagonal WO3 (h-WO3) polytypes is explored via ab initio molecular dynamics calculations within the density-functional theory framework. We present simulated finite temperature radial distribution function and X-ray diffraction patterns to reinterpret recent experimental pair distribution function analysis. This work clearly demonstrates that after a more careful analysis of the finite temperature structural properties of h-WO3, an intermediate H1-like structure is predicted at higher temperatures, while the more stable H4 polytype (and not the experimentally suggested H2 polytype) is obtained nearer ambient temperatures. This is further corroborated by our electronic structure analysis which shows that the electronic band gap energy of the ambient temperature H4-like structure agrees much better with the experimentally reported band gap energies.
Bibliographical noteFunding Information:
We gratefully acknowledge support by Creative Materials Discovery Program through the National Research Foundation of Korea (NRF) funded by Ministry of Science and ICT (2018M3D1A1058536), as well as the National Research and Development Program of Ministry of Science and ICT (2017M3A7B4032124). Computational resources have been kindly provided by the KISTI Supercomputing Center (KSC-2017-C3-0059) and the Australian National Computational Infrastructure (NCI). We thank Mr. Woosun Jang for helpful discussions in this work.
© 2018 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Physical and Theoretical Chemistry
- Surfaces, Coatings and Films