Investigation of structural, electronic, elastic and vibrational properties of HfX (X=Rh, Ru, Tc) compounds by ab-initio method

The structural, elastic, electronic, and phonon properties of HfX (X=Rh, Ru and Tc) in the CsCl phase have been investigated using the density functional theory (DFT) within the generalized gradient approximation (GGA). The optimized lattice constant (a0), bulk modulus (B) and the elastic constants (Cij) are evaluated. The results are in a good agreement with the available experimental and theoretical data in the literature. Electronic band structures and densities of states have been derived for these compounds. The present band structure calculations indicate that the phases of CsCl HfX(X=Rh, Ru and Tc) compounds are metals. Phonon dispersion curves and their corresponding total and partial density of states have been obtained for the first time by using the direct method. The phonon spectra suggest that these compounds are dynamically stable in the caesium-chloride phase.