All-electron first-principles calculations of clean surface properties of low-Miller-index Al surfaces

We report a systematic theoretical study of the clean surface properties of the Al(111), Al(100), and Al(110) surfaces as function of the film thickness employing slabs with thicknesses up to 32 angstrom. Our calculations are based on density functional theory employing the all-electron full-potential linearized augmented plane-wave (FLAPW) method. Our results show clearly a periodic oscillatory behavior of the surface energies, work functions, interlayer relaxations, total density of states at the Fermi level as function of the stab thickness, however, similar behavior is not found for the occupied bandwidth at the F point. The magnitude of the oscillations decrease with an increase of the number of layers in the slab, as expected. We found that the period of the oscillations are almost the same for Al(111) and Al(110), however, the work functions and interlayer relaxations obtained for Al(100) show oscillations with a larger period (almost by a factor of two) compared to the Al(111) and AI(110) surfaces, which are explained in terms of the deep penetration of the surface states into the bulk region of the Al(100) surface. This new physical result, as well as the agreement between our FLAPW calculations and the available experimental results, axe discussed in this paper.