Surface electronic structure of Mg(0001)

Abstract

Mg(0001) has been studied with angle-resolved photoemission spectroscopy for photon energies in the range 7.0-26.8 eV. The polar-angle dependence of the photoelectron emission was recorded along the two symmetry lines $\overline{\ensuremath{\Gamma}}\overline{M}$ and $\overline{\ensuremath{\Gamma}}\overline{K}$ of the surface Brillouin zone. Six structures are identified in the spectra. Two sharp peaks are assigned to emission from surface states. One is located in a band gap around $\overline{\ensuremath{\Gamma}}$, the other in a band gap near $\overline{M}$. Three peaks are interpreted as indirect transitions from different electron pockets in the Brillouin zone. These regions with high densities of occupied states are located close to $\ensuremath{\Gamma}$, $L$, and $K$ in the bulk Brillouin zone. Our experiments confirm earlier magnetoacoustic attenuation and de Haas---van Alphen experiments with respect to these electron pockets. Finally one broad structure is interpreted as a direct optical transition between bulk bands.