Surface energies of simple metals from slabs: Comparison of exchange-correlation density functionals

Surface energies of some simple metals (Be, Al, Mg, Li, and Na) were calculated within density functional theory. Various approximations for the exchange and correlation were tested: local density approximation (LDA), generalized gradient approximations (GGA), and meta-generalized gradient approximation (MGGA). We used the Crystal98 code to calculate slabs with one to 10 layers using both all-electron and pseudopotential approaches. The extraction of the surface energy from the series of slab energies was done by the linear-fitting method. Our LDA and GGA results agree reasonably well with those from other authors. The MGGA values are, in general, close to LDA and higher than GGA ones, a pattern also observed in the jellium model. They also agree reasonably well with the experimental data. (C) 2004 Wiley Periodicals, Inc.