Date of Original Version
Using the technique of inverse photoemission spectroscopy we have measured the unoccupied electronic states of Na on Ni(111) as a function of Na dose on the Ni(111) surface. An image-potential surface state pinned to the vacuum level shifts towards the Fermi level and disappears for Na coverages greater than 0.07 monolayer (ML). This image state reappears at high coverage, when the Na coverage is larger than 0.6 ML and is detected at 2.4 eV above the Fermi level at 1 ML of Na coverage. A Na-induced state which we assign as the Na 3p level appears for Na coverages above 0.02 ML and shifts down towards the Fermi level with increasing coverage. We compare our results with studies of related systems.
D. Tang and D. Heskett. (1993). "Unoccupied electronic structure of Na/Ni(111)." Physical Review B, 47(16), 10695. Available at: http://dx.doi.org/10.1103/PhysRevB.47.10695