Ab initio study of the electronic structure of rhodium based intermetallic compounds under pressure

Abstract

The electronic structure of rhodium based L12 intermetallic compounds (A3B) such as Rh3Ti, Rh3Zr, Rh3Hf, Rh3V, Rh3Nb, and Rh3Ti, which find wide applications as high temperature materials are studied by means of the self-consistent tight binding linear muffin tin orbital (TB-LMTO) method. These compounds are found to crystallize in the Cu3Au type structure. The total energies are calculated as a function of volume and fitted to Birch equation of states to find the equilibrium lattice parameter and the bulk modulus. They are tabulated and compared with the available experimental data. The partial number of electrons at A- and B-site of these compounds are calculated as a function of volume. We find that there is a continuous transfer of d-electrons from the A-site to the B-site. The band structure and density of states histograms are plotted. From the density of states (DOS) histograms we find a double peak structure near the Fermi level in the case of the Rh3V, Rh3Nb, and Rh3Ta compounds whereas this kind of structure is absent in the Rh3Ti, Rh3Zr, and Rh3Hf compounds. The cohesive energy and the electronic specific heat coefficient of the compounds are also computed.