B-graphene/Co(0001) system: (a,b) XPS spectra at 4.5 at. % of boron impurities, measured at photon energy of 380 eV, (c,d) LEED images, obtained at different boron content using electron energy of 70 eV, (e) ARPES spectrum at 15 at. % B, recorded near the K-point of the two-dimensional Brillouin zone in the direction, perpendicular to ΓK. Dashed line in panel (a) indicates C 1s BE value of the pure graphene/Co(0001).