Open AccessSmall polarons and point defects in barium cerate
Author(s) -
Michael W. Swift,
Anderson Janotti,
Chris G. Van de Walle
Publication year - 2015
Publication title -
physical review. b, condensed matter and materials physics
Language(s) - English
Resource type - Journals
eISSN - 1538-4489
pISSN - 1098-0121
DOI - 10.1103/physrevb.92.214114
Subject(s) - polaron , materials science , cerium , doping , hybrid functional , impurity , barium , density functional theory , condensed matter physics , hydrogen , ab initio , ionic bonding , chemical physics , electron , ion , computational chemistry , physics , chemistry , optoelectronics , metallurgy , quantum mechanics
Publisher's PDFBarium cerate (BaCeO3) is a well-known ionic conductor of both hydrogen and oxygen. In applications, it
is frequently doped (for instance with Y) to increase stability and promote diffusion. However, the effects of
doping and native defects are not fully understood. Computational studies have been stymied by the nature
of the conduction band, which is made up of cerium 4f states. These states present a challenge to ab initio
techniques based on density functional theory within the standard approximations for exchange and correlation.
Using a hybrid functional, we investigate the effects of hydrogen impurities and native defects on the electrical
and optical properties of BaCeO3. We discuss the tendency of excess electrons or holes to localize in the form
of small polarons. We also explore the interactions of polarons with hydrogen impurities and oxygen vacancies,
and their impact on luminescence properties.University of Delaware. Department of Materials Science and Engineering