Une investigation du premier principe des propriétés du Europium pnictides EuX (X=N, P, As, Sb et Bi)

Abstract

Using the first principles calculations of the structural properties, the equilibrium lattice constants, the bulk modulis and phase transition of EuX in NaCl and CsCl structure were calculated. In addition, the magnetic moments plus the electronic band structures and band gap were performed in NaCl structure. The full-potential augmented plane wave method within the generalized-density approximation was used. Both spin-polarized and non-spin polarized calculations were performed. The magnetic and structural stabilities are determined from the total energy calculations for both nonmagnetic (NM) and ferromagnetic (FM) states. The results show that the FM phase is more stable than NM phase for all components EuX. We further predict That EuX (N, P, As and Sb) undergoes a transition from NaCl to CsCl structure, however EuBi transit from CsCl to NaCl structure which is opposite comportment. From the present study EuN, EuP, EuAS and EuBi show a half-metallic behavior while EuSb found to be a nearly half-metal by using GGA. However, by using mBJ-GGA EuN was found nearly sem-semiconductor and EuSb a semi-semiconductor whereas EuA, EuAs and EuBi were found a semi-metal. The magnetic moment is estimated found to be nearly 6 µB for all compounds, which is in good agreement with the others reported value. A small increase in magnetic moment is observed by the augmentation of atomic number.