Electronic Structure and soft magnetic properties of Se/FeSiAl (110) films

V CARDOSO SCHWINDT; J.S. ARDENGHI; P. BECHTHOLD; A. JUAN; B. SETINA BATIC; M. JENKO; E.A. GONZALEZ; P.V. JASEN

APPLIED SURFACE SCIENCE

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2015 vol. 354 p. 401 - 407

0169-4332

The Se adsorption at different coverages on DO3 FeSiAl(110) surface is studied using density functional theory (DFT). Se adsorption is favorable in almost all surface high-symmetry sites, except for the bridge site formed by Fe-Si atoms. The most stable is a hollow site formed by four Fe atoms with adsorption energy of -5.30 eV. When the coverages increase, the energies decrease in the case of hollow sites. The surface present a reconstruction after Se adsorption, being the most important at 1/2 ML. The local magnetic moment for Fe atoms increase for the type A (all nearst neighbours (nn) are Fe atoms) and decrease for the type B (nn are Fe, Si and Al atoms). The most affected metal orbitals are Fe 4s and 4p. In the case of the hollow site the surface Fe-Fe bond is weakened after Se adsorption. A Fe-Se bond is developed at all coverages in both sites being the most important on top (d_Fe-Se = 2.23Å, OP: 0.774 at 1/4 ML). The first and second layer Fe-Fe bond increase at 1/4 ML and decrease at 1/2 and 1 ML. Small Se-Se bonding interaction appear at 1/2 ML and increase noticeable for 1 ML. For the top site, the Se-Se bond appears at all coverage. The Fe-Fe surface bonds also decrease its strength with respect to the clean surface at all coverage. The first and second layer Fe-Fe bond increase at all coverage.