Surface electronic structure of theNdB6(110)clean surface studied by angle-resolved photoemission spectroscopy

Abstract

An angle-resolved photoemission study of the ${\mathrm{NdB}}_{6}(110)$ clean surface has been done in order to investigate in detail the surface electronic structure. From the dependence of the valence-band photoemission spectra on the surface condition and the exciting photon energy, we found additional peaks corresponding to the surface states on the ${\mathrm{NdB}}_{6}(110)$ surface. These surface states are located at around 1.8 eV in binding energy. The dispersion relations of these surface states were determined along the $\overline{\ensuremath{\Gamma}}\ensuremath{-}\overline{M}$ symmetry line in the surface Brillouin zone and it is found that the energy dispersion for the present surface state is about 250 meV. From the photon energy dependence and the analogy of these observations with previous results for the ${\mathrm{LaB}}_{6}(110)$ clean surface, it is concluded that the present surface states have the same specifications as those of the ${\mathrm{LaB}}_{6}(110)$ surface and are ascribed to the B $2p$ dangling bonds of the surface B framework.