Structural and electronic Properties of aluminum diboride by Using density functional theory

Abstract

In this thesis the structural and electronic properties of Aluminum Diboride were investigated with respect to density functional theory by using quantum Espresso package. The local density approximation (LDA) and the generalized gradient approximation (GGA) is used to compute the exchange correlation energy. The total minimum energy of Aluminum Diboride is performed as the function of cutoff energy and Monk horst-pack grid size. The results show that, the total minimum energy per atom is monotonically decrease with increasing cutoff energy due to variational principle. However there is no systematic trend can be predicted from just increasing the k.point sampling . The total minimum force on Aluminum Diboride is computed by displaying Aluminum atoms as the function of cutoff energy and k.point grid size by 0.05 Bohr. Moreover, the total minimum force is converged at the cutoff 60Rydberg and monk horst pack mesh of 9x9x9 k.point. In addition to this, the equilibrium lattice is 7.4 Bohr. Exprimentally the Fermi Energylevel bulk of Aluminum Diboride is about 11.7468 eV. Finally,Density of state (Dos) it is helps to undestand the behavior of state occupancy over specific energy intervals. It provide in detail of the state wich are unoccupied and the wich are occupied. We observed that , there is no band gap between conduction and valance band. So, Aluminum Diboride shows metallic properties. keywords:Aluminium Diboride,density functional theory, structural electronic, total energy, total force.