  We study the relaxations, surface energies, and work functions of low index
metallic surfaces using pseudopotential plane-wave density-functional
calculations within the generalized gradient approximation. We study here the
(100), (110), and (111) surfaces of Al, Pd, Pt, and Au and the (0001) surface
of Ti, chosen for their use as contact or lead materials in nanoscale devices.
We consider clean, mostly non-reconstructed surfaces in the slab-supercell
approximation. Particular attention is paid to the convergence of these
quantities with respect to slab thickness; furthermore, different methodologies
for the calculation of work functions and surfaces energies are compared. We
find that the use of bulk references for calculations of surface energies and
work functions can be detrimental to convergence unless numerical grids are
closely matched, especially when surface relaxations are being considered. Our
results and comparison show that calculated values often do not quantitatively
match experimental values. This may be understandable for the surface
relaxations and surface energies, where experimental values can have large
error, but even for the work functions, neither local nor semi-local
functionals emerge as an accurate choice for every case.
