First-Principles study for structural, elastic and mechanical properties of CuCoMnZ (Z=Si, Sn, Sb) Heusler alloys

Structural, elastic and mechanical properties of CuCoMnZ (Z=Si, Sn, Sb) Equiatomic quaternary Heusler alloys are studied by Density Functional Theory (DFT) with Predew, Burke and Ernzerhof Generalized Gradient Approximation (PBE-GGA). On the basis of the atomic positions there are three types of structures of these alloys named as Y-type I, Y-type II and Y-type III. Structural optimization of these alloys confirms that Y-type III is the most stable structure than other two possible structures. Three cubic elastic constants C-11, C-12 and C-44 are obtained by using self-consistent-field calculations. Elastic moduli like bulk modulus, shear modulus, Young's modulus and other mechanical parameters such as Pugh's ratio, Poisson's ratio, anisotropic ratio, Cauchy pressure, velocity of sound and Debye temperature are then calculated using these elastic constants to determine the mechanical behavior of the alloys. It is noticed that all three Heusler alloys are physically stable materials and they are ionic in nature.