First Principle Ab-initio Study of TiO$_2$

POSTER

Abstract

We report results from first principle computations of electronic properties of rutile TiO${_2}$ within the local density functional approximation (LDA). Our first principle, non-relativistic and ground state calculations employed a local density functional approximation (LDA) potential and the linear combination of atomic orbitals (LCAO) -- utilizing a self-consistently obtained, optimized basis set. We solved self-consistently both the Kohn-Sham equation and the equation giving the ground state charge density in terms of the wave functions of the occupied states. Our calculated band structure shows that there is significant O$_2p$-Ti$_3d$ hybridization in the valence bands. These bands are well separated from the conduction bands by an indirect band gap of 2.95 eV, from $\Gamma$ to R. Consequently, this work predicts that rutile TiO$_2$ is an indirect band gap material, as all other gaps from our calculations are larger than 2.95 eV. A slightly larger, direct band gap of 3.05 eV is found at the $\Gamma$ point, in excellent agreement with experiment. Our structural optimization led to lattice parameters of 4.65 {\AA} and 2.97 {\AA} for $a_o$ and c$_o$, respectively, with a u parameter of 0.3051, and a bulk modulus of 215 GPa.

Authors

  • Chinedu Ekuma

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA

  • Mark Jarrell

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA, Louisiana State University, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, Louisiana State University (LSU), Department of Physics and Astronomy, Louisiana State University, Department of Physics \& Astronomy, Louisiana State University

  • Juana Moreno

    Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803, USA, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA 70803, USA, Louisiana State University, Department of Physics and Astronomy, Louisiana State University, Baton Rouge, LA, Department of Physics and Astronomy, Louisiana State University, Department of Physics \& Astronomy, Louisiana State University

  • Diola Bagayoko

    Southern University and A\&M College, Baton Rouge, LA 70803, USA, Department of Physics Southern University and A\&M College, Baton Rouge, LA 70813, Department of Physics, Southern University and A\&M College, Baton Rouge, LA 70813