Spin-resolved appearance potential spectroscopy investigations on Fe/Cu(001) overlayers

theoretical description of spin-resolved appearance potential spectroscopy (SR-APS) developed recently to deal with bulk transition-metal systems has been extended to free surfaces of Fe-n/Cu(001). Results of previous experim ental work on fcc-Fe on top of a Cu(001) substrate were interpreted to indi cate the coexistence of a few ferromagnetically coupled Fe layers on top of nonferromagnetic Fe layers for T = 110 K. Recent theoretical work. on the other hand, found for n > 2 that the ground-state of this system correspond s to antiferromagnetically coupled Fe layers. In order to clarify this situ ation the SR-APS spectra of Fe-n/Cu(001) have been calculated assuming the metastable ferromagnetic (FM) as well as antiferromagnetic (AFM) configurat ion. While for the FM configuration pronounced deviations from experiment w ere found, a nearly perfect agreement was obtained for the AFM ground-state configuration. This means that the experimental SR-APS spectra are not in conflict with the theoretical prediction but, on the contrary, they strongl y support it.