Anisotropic lattice relaxation and uniaxial magnetic anisotropy in Fe/InAs(100)-4x2

The magnetic anisotropy and the lattice relaxation of epitaxial Fe films grown on InAs(100)-4 X 2 at room temperature have been studied using in situ magneto-optical Kerr effect and reflection high-energy electron diffraction. The experimental results demonstrate that the symmetry breaking associated with the intrinsic atomic scale structure of the reconstructed semiconductor surface induces an in-plane anisotropic lattice relaxation and an in-plane uniaxial magnetic anisotropy in the ultrathin region. We propose that this is a general phenomenon in ferromagnetic/semiconductor heterostructures.