Calculated spin and orbital moments in the surfaces of the 3d metals Fe, Co, and Ni and their overlayers on Cu(001)

The spin and orbital moments of the surfaces of Fe, Co, and Ni as well as of overlayers of these metals deposited on Cu have been calculated using a full-potential linear muffin-tin orbital method in a slab geometry. With one exception, Ni on Cu(001), the calculated spin moments are considerably enhanced at the surface, which is in agreement with previous theoretical and experimental work for some of the presently studied systems. We argue that the Ni-$d$---Cu-$d$ hybridization is responsible for the reduced Ni spin moment in the case of a Ni monolayer on a Cu(001) substrate. The orbital moment is enhanced at the surface for all of the studied cases, sometimes by as much as a factor of 2 relative to the value found in the bulk. Based on our theoretical calculations we propose that an experimental confirmation of an enhanced orbital magnetic moment on a surface is most likely to be found for a monolayer of Co on a Cu(001) substrate or for the Fe(001) surface layer. Experimental work on Co on Cu(001) confirm this behavior.