Structural and Spin Polarization Effects of Cr, Fe and Ti Elements on Electronical Properties of α –Al2O3 by First Principle Calculations
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 –Al2O3 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.
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 –Al2O3 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.
Cite this paper
nullH. Alibad and S. Ghorbani, "Structural and Spin Polarization Effects of Cr, Fe and Ti Elements on Electronical Properties of α –Al2O3 by First Principle Calculations," Journal of Modern Physics, Vol. 2 No. 3, 2011, pp. 158-161. doi: 10.4236/jmp.2011.23024.
nullH. Alibad and S. Ghorbani, "Structural and Spin Polarization Effects of Cr, Fe and Ti Elements on Electronical Properties of α –Al2O3 by First Principle Calculations," Journal of Modern Physics, Vol. 2 No. 3, 2011, pp. 158-161. doi: 10.4236/jmp.2011.23024.
References
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[1] W. H. Gitzen, “Alumina as a Ceramic Material,” American Ceramic Society, Columbus (OH), 1970. [2] K. P. Driver, “The Role of Relativity in Magnetism, Calculating Magnetic Moments in Solids,” Submitted to the Graduate School for the Doctoral candidacy, Department of Physics, the Ohio State University, 2006. [3] R. Laskowski, “Magnetism and Soc in Wien2k,” Vienna University of Technology, Institute of Materials Chemistry, wien2k workshop, 2006. [4] P. Blaha, K. Schwarz, G. Madsen, D. Kvasnicka and J. Luitz, Institute of Materials Chemistry, TU Vienna, 2011. http://www.wien2k.at/ [5] S. M. Hosseini, H. A. Rahnamaye Aliabad and A. Kompany, “Influence of La on Electronic Structure of α-Al2O3 High K-Gate from First Principle,” Ceramics International, Vol. 31, No. 5, 2005, pp. 671-675. doi:10.1016/j.ceramint.2004.07.008 [6] W. Tews and R. Gundler, “α–Al2O3 and γ–Al2O3 Energy Loss Data,” Physica Status Solidi, Vol. 109, 1982, pp. 255-264. doi:10.1002/pssb.2221090128 [7] R. H. French, D. J. Jones and S. Loughin, “Interband Electronic Structure of α–Al2O3 up to 2167 K,” Journal of American Society, Vol. 77, 1994, pp. 412-422. [8] R. H. French, “Electronic Structure of α–Al2O3, with Comparison to AlON and AlN,” Journal of American Society, Vol. 73, No. 3, 1990, pp. 477-489. [9] Y. Yourdshahyan, C. Roberto, M. Halvarsson, L. Bengtsson, V. Langer and B. Lundqvist, “Theoretical Structure Determination of Complex Material: Kappa-Al2O3,” Journal of American Society, Vol. 82, No. 6, 1999, pp. 1365-1445. [10] I. Oleinik, E. Yu Tsymbal and D. G. Pettifor, “Structural and Electronic Properties of Co/Al2O3/Co Magnetic Tunnel Junction from First Principles,” Physics Review B, Vol. 62, 2000, pp. 3952-3959. doi:10.1103/PhysRevB.62.3952