First-principles study on the crystal, electronic structure and stability of LaNi5−xAlx (x=0, 0.25, 0.5, 0.75 and 1)

The crystal, electronic structures and stability of LaNi5-xAlx (x = 0, 0.25, 0.5, 0.75 and 1) have been investigated using a planewave pseudo-potential method. It shows that aluminum atoms tend not to be close to each other and prefer to be set dispersedly in all planes B (the plane where 3g sites lie) rather than in partial ones. The formation and cohesive energy of LaNi5-xAlx alloy is calculated and analyzed. Aluminum induces Ni-d bands to be narrowed and the interaction of Ni-d with Al-sp and La-d to be weakened. The covalence and ionicity analysis shows that the interactions of Ni with Al and La are mainly covalent and ionic, respectively. The relationship of the formation energy of LaNi5-xAlx to its electronic structures shows that the total electronic densities of states at E-F changes with x with the almost same trend to the formation energy of LaNi5-xAlx. The interaction between Ni and Al plays a dominant role in the stability of LaNi5-xAl(x). (c) 2005 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.