Spin-split image-potential-induced surface state on Ni(111)

Spin-resolved inverse photoemission measurements of the n=1 image-potential-induced surface state on Ni(111) reveal a magnetic exchange splitting of 18±{}3 meV. The size of the splitting is in accord with calculations within the one-step model of inverse photoemission assuming the barrier potential as spin independent, but taking into account the different energy positions of the spin-up and spin-down band-gap boundaries. It is shown that spin resolution in experiments enables detection of splittings considerably smaller than the linewidths of the spectral features.