AVS 51st International Symposium
    Surface Science Wednesday Sessions
       Session SS1-WeA

Paper SS1-WeA1
First-Principles Study of Intrinsic Defect Formation Energies in Tio@sub 2@

Wednesday, November 17, 2004, 2:00 pm, Room 210B

Session: Metal Oxides and Clusters II: TiO@sub 2@ and Photocatalysis
Presenter: J. He, University of Florida
Authors: J. He, University of Florida
S.B. Sinnott, University of Florida
Correspondent: Click to Email
First-principles calculations are used to study intrinsic defects in bulk rutile TiO@sub 2@ and on the TiO@sub 2@ (110) surface. The approach is density functional theory (DFT) using the generalized gradient approximation (GGA) combined with plane-wave ultrasoft pseudopotentials. In particular, the formation energies of isolated vacancies, interstitials, and substituents with different charges, representing localized or distributed charge states, are evaluated. The DFT calculation results are combined with thermodynamic data to calculate the defect formation energies. In particular, the influence of temperature and oxygen partial pressure on the oxygen chemical potential is taken into account. The calculations suggest that fully charged Ti interstitials are more stable than oxygen vacancies at most oxygen partial pressures. Contrary to expectations, our preliminary results also indicate that the formation energy behavior of O vacancies at the TiO@sub 2@(110) surface is similar to the formation energy behavior of O vacancies in bulk TiO@sub 2@. These results are helping us to understand defect formation and segregation in TiO@sub 2@.