Structural and Spin Polarization Effects of Cr, Fe and Ti Elements on Electronical Properties of α –Al<sub>2</sub>O<sub>3</sub> by First Principle Calculations
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Abstract
Structural and spin polarization effects of Cr, Fe and Ti elements on electronical properties of alumina have been studied by using of Local spin density approximation within density functional theory. The calculated results indicated that substituting aluminium atoms by these dopants have a significant influence on the structural and electronic properties of α –Al<sub>2</sub>O<sub>3</sub> crystals. Band gap of alumina decreases with the substitution of these impurities. Results show that band gap is different for spin-up and down (spin splitting effect). Among these impurities the effect of Ti on size of the energy gap is small in comparison with Cr and Fe. It is suggested that the origin of electrons spin splitting is appeared from exchange energy of d-states. These results may be useful to obtain a physical beheviour of transition metals for electrons spin polarization in d-states.
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