Theory of dopants and defects in Co-doped TiO2 anatase

Abstract

We report first-principles microscopic calculations of the formation energy, electrical activity, and magnetic moment of Co dopants and a variety of native defects in TiO2 anatase. Using these results, we use equilibrium thermodynamics to predict the resulting carrier concentration, the average magnetic moment per Co, and the dominant oxidation state of Co. The predicted values are in good agreement with experiment under the assumption of O-poor growth conditions. In this regime, a substantial fraction of Co dopants occupy interstitial sites as donors. The incomplete compensation of these donors by substitutional Co acceptors then leads to n-type behavior, as observed experimentally.

8 pages, 3 figures, 1 table, revised

References in corpus (2)

• Electronic structures of doped anatase $\mathrm{Ti}{\mathrm{O}}_2$: $\mathrm{T}{\mathrm{i}}_{1-\mathrm{x}}{\mathrm{M}}_{\mathrm{x}}{\mathrm{O}}_2$ (M=Co, Mn, Fe, Ni)
• Origin of room-temperature ferromagnetism in Mn doped semiconducting CdGeP2

Cited by in corpus (5)

• Dual behavior of excess electrons in rutile TiO2
• Calculation of point defects in rutile TiO2 by the Screened Exchange Hybrid Functional
• The role of transition metal impurities and oxygen vacancies in the formation of ferromagnetism in Co-doped TiO2
• Co distribution in ferromagnetic rutile Co-doped TiO${}_2$ thin films grown by laser ablation on silicon substrates
• Metal-to-insulator transition in anatase TiO2 thin films induced by growth rate modulation