Electronic structure of non-stoichiometric titanium hydride

Abstract The electronic structure of non-stoichiometric TiHx (0 ⩽ x ⩽ 2) was studied by calculating the energy bands of model supercells where the hydrogen atoms occupy various tetrahedral sites of the f.c.c. lattice to represent TiHx with x = 0,0.25,…, 1.75,2. It is shown that one new state is formed below the Fermi level per hydrogen atom and therefore the Fermi level does not shift with respect to the d bands. A sharp peak in the density of states at the Fermi level is present for TiH2 and TiH1.75 but not clearly for TiH1.5, which confirms that the tetragonal distortion of TiHx with 1.8