Phase stability and electronic structure in ZrAl3 compound

The relative stabilities of L1 2 , D0 22 , and D0 23 structures in the ZrAl 3 intermetallic compound have been investigated employing the Vienna ab initio simulation package (VASP). The effects due to the tetragonal distortion of the D0 22 and D0 23 structures are important. The effect of the cell-internal displacements of the atoms in the D0 23 structure is studied. The more stable structure is D0 23 followed by D0 22 and by L1 2 . The calculations show that at high pressure L1 2 becomes more stable than D0 22 . The energies of formation of ZrAl 3 in the L1 2 , D0 22 , and D0 23 structures are calculated. The computed electronic densities of states show that each structure has a pseudo gap in the density of states distribution. The preferred crystal structure is the one in which the Fermi level lies in the pseudo gap and for which the density of states at the Fermi level is the lowest. The energetic results are discussed in the framework of the ANNNI model.