Interface bonding for Fe thin films on GaAs surfaces of differing morphology

Formation of a common type of Fe-As local bonding in Fe thin films on GaAs surfaces of differing orientation and preparation is evidenced through a common charge transfer at the interface. X-ray absorption studies of unoccupied $3d$ states for Fe thin films on sputtered GaAs(100) and cleaved GaAs(110) display a similar amount of $3d$ charge transfer into the GaAs substrate even though the mode of surface preparation leads to reduced intermixing in the (100) case. Implications of these results for the understanding of the role of the Fe-GaAs interface in both electronic and magnetic properties are discussed.