2009/05/24 by V. Kanchana, G. Vaitheeswaran, Yanming Ma +4 · 1 citation
Engineering · Materials Science · Mathematics · Physics and Astronomy · #Boron and Carbon Nanomaterials Research #Bulk modulus #Condensed matter physics #Debye model #Density functional theory #Density of states #Dispersion relation #Elastic modulus #Heusler alloys: electronic and magnetic properties #Intermetallics and Advanced Alloy Properties #Lattice constant #Materials science #Mathematics #Phonon #Physics #Poisson distribution #Poisson's ratio #Quantum mechanics #Shear modulus #Thermodynamics #Video Graphics Array #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.80.125108
14 pages, 3 figures
arxiv created 2009/05/24 · openalex publication_date 2009/09/11 · arxiv updated 2015/05/13 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
The structural and elastic properties as well as phonon-dispersion relations of the Heusler-type alloys Fe2VAl and Fe2VGa are computed using density functional and density-functional perturbation theory within the generalized-gradient approximation. The calculated equilibrium lattice constants agree well with the experimental values. The elastic constants of Fe2VAl and Fe2VGa are predicted. From the elastic constants the shear modulus, Young's modulus, Poisson's ratio, sound velocities, and Debye temperatures are obtained. By analyzing the ratio between the bulk and shear moduli, we conclude that both Fe2VAl and Fe2VGa are brittle in nature. The computed phonon-dispersion relation shows that both compounds are dynamically stable in the L21 structure without any imaginary phonon frequencies. The isomer shifts in Fe in the two compounds are discussed in terms of the Fe s partial density of states, which reveal larger ionicity/less hybridization in Fe2VGa than in Fe2VAl. For the same reason the Cauchy pressure is negative in Fe2VAl but positive in Fe2VGa.