The investigation of l21 in the structure, heusler type Ni2XGa (X=Co, Cu, Ni, Sc, Ti, V ve Zn) alloys, in terms of their structural, electronic, elastic and phonon properties using density functional theory

In this thesis, elastic, electronic, and phonon properties of Ni2XGa (X=Co, Cu, Ni, Sc, Ti, V ve Zn) Heusler alloys in L21 structure have been investigated via first-principles calculations within the generalized gradient approximation. Ground state properties such as lattice constant, bulk modulus and its first derivative have been determined by fitting the total energy as a function of the volume to the Murnagan equation of states. The computed elastic constants for Ni2CoGa, Ni2CuGa ve Ni2NiGa alloys are unstable by Born stability criteria, while the ather alloys are stable. The electronic band structure of these materials is presented by including spin-polarized state. The calculated total magnetic moment for Ni2CoGa has been founded as 1.90 µB, while the other materials have been calculated as 0 μB. The phonon-dispersion curves based on the linear-response method have been investigated for all materials. According to these results, the phonon properties of all materials have been found as dynamically unstable.