Through systematic density functional calculations, the mechanism of the substrate induced spin reorientation transition in $\mathrm{FePc}/\mathrm{O}\mathrm{\text{−}}\mathrm{Cu}(110)$ is explained in terms of charge transfer and rearrangement of Fe-$3d$ orbitals. Moreover, we find giant magnetoelectric effects in this system, manifested by the sensitive dependence of its magnetic moment and magnetic anisotropy energy on an external electric field. In particular, the direction of magnetization of $\mathrm{FePc}/\mathrm{O}\mathrm{\text{−}}\mathrm{Cu}(110)$ is switchable between in-plane and perpendicular axes, simply by applying an external electric field of $0.5\mathrm{eV}/\AA$ along the surface normal.

• Received 3 August 2012

DOI:https://doi.org/10.1103/PhysRevLett.110.097202