Anisotropic lattice relaxation and uniaxial magnetic anisotropy in $\mathrm{F}\mathrm{e}/\mathrm{I}\mathrm{n}\mathrm{A}\mathrm{s}\left(100\right)\mathrm{}-4\mathrm{}\times 2$

The magnetic anisotropy and the lattice relaxation of epitaxial Fe films grown on $\mathrm{InAs}\left(100\right)\mathrm{}-4\mathrm{}\times 2$ 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.