Atomistic calculations were performed on a slab model of the (0001) surface of hematite as well as the bulk structure. In particular, the energetics of oxygen vacancies near the surface was studied. Atomistic modeling was used to establish the defect energies in the bulk versus distance from the surface. Transition state calculations were performed to compute barriers for several pathways of migration of oxygen vacancies in the bulk and at varying depths relative to the surface. We find energy barriers of several transitions considerably lowered closer to the surface. Considerations of literature data for electrical conductivity and Seebeck coefficient on bulk versus thin-film hematite suggest high populations of point defects near surfaces, in agreement with our predictions.
|Number of pages||8|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - Jan 2002|
ASJC Scopus subject areas
- Ceramics and Composites