Hamburg 2001 – wissenschaftliches Programm

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DS: Dünne Schichten

DS 3: Schichteigenschaften I

DS 3.2: Vortrag

Montag, 26. März 2001, 11:15–11:30, S 5.1

FP-LAPW studies of oxygen-induced changes in structure and magnetic properties on Fe/Cu(001) — •Xilin Yin and Klaus Hermann — Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin

Oxygen-induced changes in structure and magnetic properties on ultra-thin Fe films up to three layers on Cu(001) (Cu(001)-Fe_(n), n = 1, 2, 3) are studied using first principles density functional theory as implemented by the full-potential linearized augmented plane wave (FP-LAPW) method. Studies of p(1×1) oxygen adlayers on top of the Cu(001)-Fe_(n) systems show the 4-fold high coordination site as the most favorable site for oxygen. The oxygen and topmost Fe layers become almost co-planar forming a slightly buckled FeO(001) type film, however, with a lateral lattice constant increased by 18% wrt. bulk FeO. Oxygen is found to decrease the magnetic moment of the topmost Fe layer while the moments of the deeper Fe layers are increased. Studies on sub-surface oxygen below the topmost Fe layer yield an energetically less favorable situation compared with that of adsorbed oxygen. This can give rise to diffusion of sub-surface oxygen above the Fe film as found in model studies on the Cu(001)-O-Fe₍₁₎ system which transforms to Cu(001)-Fe₍₁₎-O without an energy barrier. Further, sub-surface oxygen is found to stabilize oxygen adsorbate layers.