Ab-initio Investigation of the Hydrogenation of Y
Garnier, Michael Bernard Gunnar
Date de parution
Physica Scripta, Institute of Physics (IOP), 2004/T109//163-165
We present an <i>ab-initio</i> electronic structure study of a face centred (fcc) cubic Y lattice, which is subsequently filled with hydrogen in tetrahedral and octahedral sites. The stoichiometry of the calculated compounds is Y, YH<sub>2</sub><sup>tetra</sup>, YH<sub>3</sub> and YH<sub>1</sub><sup>octa</sup>. Upon placement of hydrogen in tetrahedral sites we note for the YH<sub>2</sub><sup>tetra</sup> phase a new, fully occupied hydrogen related band and a redistribution in the d-band manifold at the Fermi level. Interestingly during the fcc Y → YH<sub>2</sub><sup>tetra</sup> transition the overall topology of the Fermi surface (FS) is not changed, but we note a change in character from t<sub>2g</sub> to e<sub>g</sub> of the responsible band. It is this change to e<sub>g</sub> character which allows subsequent H in octahedral sites to significantly interact with the FS, finally enabling the metal-insulator transition while reaching YH<sub>3</sub>. A placement of hydrogen solely in octahedral sites does not affect significantly the t<sub>2g</sub> d-band at the Fermi level.
Type de publication
Resource Types::text::journal::journal article