The formation of hexagonal boron nitride $\left(h\text{−}\mathrm{B}\mathrm{N}\right)$ monolayers on Ni(111), Rh(111), and Pt(111) has been studied by a combination of x-ray emission, angle-resolved valence band photoemission, and x-ray absorption in search for interface-induced gap states of $h\text{−}\mathrm{B}\mathrm{N}$. A significant density of both occupied and unoccupied gap states with $\mathrm{N}2p$ and $\mathrm{B}2p$ characters is observed for $h\text{−}\mathrm{B}\mathrm{N}∕\mathrm{Ni}\left(111\right)$, somewhat less for $h\text{−}\mathrm{B}\mathrm{N}∕\mathrm{Rh}\left(111\right)$ and still less for $h\text{−}\mathrm{B}\mathrm{N}∕\mathrm{Pt}\left(111\right)$. X-ray emission shows that the $h\text{−}\mathrm{B}\mathrm{N}$ monolayer is chemisorbed strongly on Ni(111) and very weakly on Pt(111). We associate the gap states of $h\text{−}\mathrm{B}\mathrm{N}$ adsorbed on the transition metal surfaces with the orbital mixing and electron sharing at the interface because their density increases with the growing strength of chemisorption.

• Received 22 May 2007

DOI:https://doi.org/10.1103/PhysRevB.77.085421