Surface electronic structure of metals

Abstract

The surface electronic structure calculations of Sr(001), Cd(0001), In(001), Ba(001), Pb(001), and Hf(001) are performed using the self-consistent pseudopotential method. It is shown that there is a developed system of unoccupied surface states at Sr, Ba, Pb, and Hf surfaces. For Sr an occupied surface state is found at the X̄ point of the two-dimensional Brillouin zone. In the energy gap at \\ ̄ gG the surface state is located above the Fermi level. In the case of Cd the surface state is not observed in the gap at \\ ̄ gG. The 5% contraction of the top interlayer spacing does not change the result. For the Cd(0001) surface with the ideal casec a axial ratio the calculation of the electronic structure showed that in such a hypothetical lattice there exists a surface state in the energy gap at \\ ̄ gG. The electronic structure of the In(001) surface is similar, in many respects, to the band structure of the Al(001) surface. On the Ba(001) surface the occupied surface state is found only at the X̄ point. On the Pb(001) surface occupied surface states are observed at X̄ and M̄. Like a Cd surface there is no surface state in the energy gap at the \\ ̄ gG point of the Brillouin zone of Pb(001). The electronic states of the Hf(001) surface can be obtained by means of energy shifts from the electronic states of the Ba(001) surface.