Electronic And Structural Properties of Zirconium Dibo ride (Zrb2) Using Density Functional Theory (Quantum Espresso)

Abstract

In this thesis the rst principle calculation of Zirconium diboride (ZrB2) is investigated with density functional theory (DFT) using Quantum Espresso package. Our study is based on Density Functional Theory (DFT) with the Perdew-Burke-Ernzerhof (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 ZrB2 is calculated as a function of cuto energy and K-points sampling. The total minimum energy per cell is monotonically decreasing with increasing cuto energy due to variational 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 13 Ö 13 Ö 11 k points). The computational value of the equilibrium lattice constant is 6.0056 Bohr. This result is in good agreement with experimental value which is 6.0102 Bohr. Finally, discussing band structure and density of state of ZrB2 , the electrical property of ZrB2 is determined based on energy band gap. Keywords: Zirconium Diboride, Density Functional Theory, Electronic and structural properties