Relaxation of Cu(100), (110) and (111) surfaces using ab initio pseudopotentials

The geometries of the Cu(100), Cu(110) and Cu(111) surfaces are determined using ab initio pseudopotential calculations. Use of the Hellmann-Feynman t heorem to calculate forces allows the determination of the equilibrium atom ic positions with a small number of trial geometries. Our calculated result s show that the surface relaxation of Cu(100) and Cu(110) surfaces are inwa rd relaxations, while that of Cu(111) surface is slightly outward relaxatio n. Our results show that the forces, charge transfer and the detailed elect ronic structure of the Cu surface will affect the relaxation of the outermo st layer. The calculated results are in good agreement with the results obt ained by various experiments.