Eur. Phys. J. B 29, 61-69 (2002)
https://doi.org/10.1140/epjb/e2002-00262-2

Electronic structure of LaNi₅ and its hydride LaNi₅H₇

¹ Pohl Institute of Solid State Physics, Tongji University, Shanghai 200092, PR China
² Beijing Institute of Applied Physics and Computational Mathematics, Beijing 100088, PR China

Corresponding author: ^a zhenghp@mail.tongji.edu.cn

Received: 13 July 2001
Revised: 10 December 2001
Published online: 17 September 2002

Abstract

The electronic structure of LaNi₅ and its hydride LaNi₅H₇ are obtained using the self-consistent cluster-embedding calculation method. The Fermi level of LaNi₅H₇ is 5.172 eV higher than that of LaNi₅. In both materials, the La 5d electrons locate nearby the Fermi levels, and make only a small contribution to the density of states (DOS) of the valence bands. There is no significant charge transfer from La to Ni in LaNi₅. But for LaNi₅H₇, there is a charge transfer of 1.16 electrons from La to H, and H atoms are combined mainly with Ni to form hybridized orbitals in the energy regions far below the Fermi level. An explanation of hydrogenation of LaNi₅ is proposed: It is easy for hydrogens to take off some localized La 5d electrons near the Fermi level, and combine with Ni to form hybridized orbitals in lower energy regions. This process is therefore in favor of energy, and forces a lattice expansion until the Fermi level rises to zero.