Valley spin polarization of Tl/Si(111)

Metal/semiconductor hybrid systems are attractive for integrating spintronic devices on current semiconductor technology. This paper investigates the potential of Tl/Si(111), a system with an unoccupied surface state within the silicon band gap, which forms fully spin-polarized valleys at the $\overline{\mathrm{K}}$ and ${\overline{\mathrm{K}}}^{\ensuremath{'}}$ points close to the Fermi level. Our key findings are the robustness of the system against contamination and the possibility to dope the system such that the fully spin-polarized valleys become metallic. This establishes Tl/Si(111) as possessing all necessary key properties for spintronic applications.