Electronic dispersion relations of monolayer hexagonal boron nitride formed on the Ni(111) surface

Angle-resolved ultraviolet-photoelectron spectroscopy and angle-resolved secondary-electron emission spectroscopy have been carried out for a film of single-crystalline hexagonal boron nitride (h-BN) formed on the Ni(111) surface to investigate both the valence- and conduction-band structures. The thickness of the film studied in this experiment was 1 ML. The observed electronic dispersion relations were compared with some theoretical ones reported for bulk h-BN. Among these theoretical calculations, the one by Catellani et al. [Phys. Rev. B 36, 6105 (1987)] is in the best agreement with the present results. We have discussed the strength of the interfacial bond and the influence of this bond upon the electronic states of the monolayer h-BN film on the basis of the observed band structures for the BN film and a film of monolayer graphite formed on Ni(111).