Investigation of changes in crystal and electronic structures by hydrogen within LaNi₅ from first-principles

Adel F. Al Alam (1) , Samir F. Matar (1) , M. Nakhl (2) , N. Ouaini (3)

1 ICMCB - Institut de Chimie de la Matière Condensée de Bordeaux
2 Faculté des Sciences
3 Faculté des Sciences et de Génie Informatique

Hydrogenation of LaNi₅ P6/mmm, up to saturation brings modifications of the crystal structure with two possible space groups for LaNi₅H₇, i.e. P6₃mc and P31c, determined experimentally. The energetics from computations within DFT allows pointing to the former as the most favorable one within a doubled cell along the c-axis with respect to LaNi₅. Results also show a compensation of the volume expansion effects favorable to the onset of magnetization by the chemical bonding involving Ni–H bond leading to vanishing moments.

Mots clés: Haucke phase; Hydride; DFT; VASP; ASW; Magnetic order; Chemical bonding; Bulk modulus; Electronic specific-heat coefficient

Domaines: Matériaux

Adel F. Al Alam, Samir F. Matar, M. Nakhl, N. Ouaini. Investigation of changes in crystal and electronic structures by hydrogen within LaNi₅ from first-principles. Solid State Sciences, 2009, 11 (6), pp.1098-1106. ⟨10.1016/j.solidstatesciences.2009.02.026⟩. ⟨hal-00392713⟩