Calculations of the electronic properties of substoichiometric Ti-Fe hydride

We have calculated the electronic structure of ${\mathrm{TiFeH}}_{\mathrm{x}}$ using the tight-binding coherent-potential-approximation method. The tight-binding parameters were determined by Slater-Koster fits to augmented-plane-wave calculations of TiFe and ${\mathrm{TiFeH}}_{1.0}$. We have computed the densities of states (DOS) for the hydrogen concentrations x=0.1, x=0.8, and x=0.9, and obtained the angular-momentum and site-decomposed DOS. We have found that the Fermi level $E_F$ is very nearly independent of x, but the DOS values at $E_F$ increase rapidly with x in agreement with experiment. We discuss various features of the DOS relating to the effects of hydrogenation and disorder.