Electronic and structural properties of Titanium dibo ride (Tib2) Using Density Functional theory

Abstract

In this thesis the first principle calculation of Titanium Diboride (TiB2 ) is investigated with den sity functional theory (DFT) using Quantum Espresso package. Our study is based on Density Functional Theory (DFT) with the Perdew-Burke-Ernzerhof (GGA-PBE) exchange-correlation functional, Vanderbilt (ultra soft) pseudo-potentials and the plane wave basis set implemented in the Quantum-ESPRESSO package. The calculation of the total minimum energy of TiB2 is calculated as a function of cutoff energy and K-points sampling. The total minimum energy per cell is monotonically decreasing with increasing cutoff energy due to variation principle. However, this trend can not be predicted from increasing the k-points sampling. Moreover, the equilibrium lattice constant is calculated using results obtained from energy convergence test (i.e., 60 Ry and 12 × 12 × 10 ). The computational value of the equilibrium lattice con stant is 5.725527Bohr. This result is in good agreement with experimental value which is 5.735527Bohr . Finally, discussing band structure and density of state of TiB2 , the electrical property of TiB2 was determined based on energy band gap and it is a conductive material, often showing metallic behavior.