Density functional theory study of Selenium adsorption on Fe(110)

E. A. GONZALEZ; P. V. JASEN; M. SANDOVAL; P. BECHTHOLD; A. JUAN; B. SETINA BATIC; MONIKA JENKO

APPLIED SURFACE SCIENCE

ELSEVIER SCIENCE BV

Año: 2011 vol. 257 p. 6878 - 6883

0169-4332

The adsorption of atomic Se on the Fe(110) surface is examined using density functional theory (DFT). Selenium is adsorbed in the high-symmetry adsorption sites: bridge (short and long), and atop sites in the following surface arrangements: p(2x2), c(2x2) and p(1x1) which correspond to coverages of 1/2, 1/4 and 1 monolayer (ML), respectively. The long bridge site is found to be the most stable, followed by the short bridge and top sites. The adsorption energy is -5.23eV for the p(2x2). The Se adsorption results in a surface reconstruction, with the most significant being that for the long bridge site, with lateral displacements of ± 2%, affecting the 1st and 2nd neighbours. Comparisons between Se-adsorbed and pure Fe surfaces revealed reductions in the magnetic moments of surface-layer Fe atoms in the vicinity of the Se. At the long bridge site, the presence of Se causes an decrease in the surface Fe d-orbital density of states between 4 and 5 eV below the Fermi level. The density of states present a contribution of Se states at -3.2 eV and -12.9 eV stabilized after adsorption. The Fe-Fe overlap population decrease and a Fe-Se bond are formed at expenses of the metallic bond.