Atomic structure and electronic properties of Ni₃Al(111) and (011) surfaces

We present results of theoretical studies of the structural and electronic properties of (111) and (011) surfaces of paramagnetic Ni 3 Al alloy. Atomic and electronic structures of these surfaces have been obtained from the density-functional calculations performed with the use of plane wave basis set. Our ab initio calculations show that for all considered surfaces, the topmost Al atoms are located above Ni atoms, and the structural parameters of relaxed surface systems well correspond to experimental data provided by earlier low-energy electron-diffraction measurements. The details of the calculated electronic structure of Ni 3 Al(111) in the vicinity of the Fermi level were compared with the results of scanning tunneling spectroscopy (STS) measurements which we have performed for this system, and a good agreement has been found between the calculated local-density-of-states distributions and the shape of obtained STS spectra.