ELECTRONIC AND MAGNETIC-PROPERTIES OF A CO-MONOLAYER ON A W(110) SUBSTRATE

We have carried out a full potential linearized augmented plane wave-(FLAPW-) calculation on a pseudomorphic Co-monolayer in contact with a W(110) substrate. A detailed study of this system appeared to be much desirable because it represents one of the rare cases where the experimental conditions allow an almost perfect preparation of the ideal system which the calculations refer to. The system lends itself to a study of the problem how the ferromagnetic order of a Co-monolayer can survive in close contact with a paramagnetic substrate. To demonstrate the vulnerability of the spin order in that monolayer we have performed calculations for various adlayer-substrate distances including those cases which are most frequently discussed in the literature. As opposed to Ag substrates, for example, W interacts rather strongly with the polarized Co-electrons because its d-states extend over the same energy regime as the corresponding d-states of the Co-layer. This is in keeping with the theoretical result that the magnetic moment of the Co-layer drops very sensitively as the adlayer-substrate distance decreases. Certain portions of the band structure which relate to surface localized states agree fairly well with those obtained from recent photoemission experiments by Knoppe and Bauer [to appear in Phys. Rev. B]. Additional features of the band structure which are also associated with well defined surface enhanced states are obviously not accessible to the experiment for reasons which are not yet understood.