ELECTRONIC-STRUCTURES AND SURFACE MAGNETISM OF NI(100) AT FINITE TEMPERATURES

Magnetic and one-electron properties of Ni(100) at finite temperatures are studied by our recently developed calculation method in which effects of spin fluctuations on the first ten layers of the semi-infinite fcc lattice, described by the realistic canonical d-band model, are included by means of the functional-integral method within the static and single-site coherent potential approximations. It is shown that the surface moment, whose ground-state value is slightly enhanced compared with the bulk one, decreases more rapidly than the bulk upon heating. The calculation of spectral densities indicates that their exchange-split peaks at all the investigated wave-vectors in the surface Brillouin zone approach each other with broadened linewidths when the temperature is raised. The recent ARPE experiments probing the bulk band structure are discussed on the basis of the calculated surface and bulk spectral densities.