Rippled surface structure and electronic and magnetic properties of Ni₃al(001)

Structural, electronic, and magnetic properties of Ni₃Al(001) are investigated by the all-electron thin film full-potential linearized augmented plane wave method based on the local density approximation. A stable rippled surface atomic geometry is determined by atomic force and total energy calculations. The surface Ni atoms contract down to the bulk region by 4.2% of the bulk interlayer spacing while all of the other atoms including the surface Al atoms remain close to their bulk positions. The amount of rippling found by calculation (0.06 Å) is almost within experimental error (0.02 ± 0.03 Å). Charge densities, calculated work functions, and densities of states for the relaxed rippled and unrelaxed surfaces are reported. The spin polarized calculation predicts that the Ni₃Al(001) surface is "magnetically dead," unlike the bulk region.