Surface electronic and magnetic properties of semiconductor FeSi

First-principles local spin-density functional calculations of the electronic and magnetic properties of semiconducting FeSi (111) surface with both Fe- and Si-terminations have been performed. It is found that the Fe-terminated (111) surface is strongly ferromagnetic with a magnetic moment of 2.6μB/atom on the top Fe monolayer while the Si-terminated (111) surface is only weakly magnetic or nonmagnetic. These interesting results suggest that a semiconductor-based spintronics device might be developed by using thin FeSi (111) films connected to a metal lead on the Fe-terminated surface and to a semiconductor substrate on the Si-terminated surface.