Evaluation of thermodynamics, formation energetics and electronic properties of vacancy defects in CaZrO₃

Using first-principles total energy calculations we have evaluated the thermodynamics and the electronic properties of intrinsic vacancy defects in orthorhombic CaZrO₃. Charge density calculations and the atoms-in-molecules concept are used to elucidate the changes in electronic properties of CaZrO₃ upon the introduction of vacancy defects. We explore the chemical stability and defect formation energies of charge-neutral as well as of charged intrinsic vacancies under various synthesis conditions and also present full and partial Schottky reaction energies. The calculated electronic properties indicate that hole-doped state can be achieved in charge neutral Ca vacancy containing CaZrO₃ under oxidation condition, while reduction condition allows to control the electrical conductivity of CaZrO₃ depending on the charge state and concentration of oxygen vacancies. The clustering of neutral oxygen vacancies in CaZrO₃ is examined as well. This provides useful information for tailoring the electronic properties of this material. We show that intentional incorporation of various forms of intrinsic vacancy defects in CaZrO₃ allows to considerably modify its electronic properties, making this material suitable for a wide range of applications.