First-principles study of iron segregation into silicon ∑5 grain boundary

Abstract

Using ab initio density function theory total energy calculations, we have investigated the mechanism of Fe segregation into Si ∑5⟨310⟩ grain boundary (GB). We find that the segregation is site selective at the GB—Fe will only segregate to specific sites. We further find that the choice of the segregation site is determined by the segregation-induced stress and effective crystal-field-induce splitting of Fe d orbital at that site. Our results suggest that the revealed mechanism of Fe segregation into the GB should be general for other 3d transition metals with partially filled 3d orbits and for other grain boundaries.