A study on native defects and magnetic properties in undoped rutile TiO_2 using LDA and LDA+U_(O p)+U_(Ti d) methods

摘要

The native defects and magnetic properties in undoped rutile TiO_2 are studied using local density approximation (LDA) and LDA adding Hubbard parameters (U) schemes. The band gap is adjusted to experimental value of 3.0 eV by combination of U_(Ti d) d=4.2 eV and U_(O p)=4.8 eV. This LDA+ U methodology overcomes the band-gap problem and renders the approach more predictive. The formation energies of oxygen vacancy (V_O), oxygen interstitial (O_i), titanium vacancy (V_(Ti)), titanium interstitial (Ti_i), oxygen anti-sites (O_(Ti)), and titanium anti-sites (Ti_O) are investigated by the LDA and LDA+U methods. In addition, some ground state configurations can be obtained by optimization of total spin. It is found that native defects can induce spin polarization and produce magnetic moment.