Spin-polarized surface state in Li-doped SnO2(001)

Abstract

Using LDA + U, we investigate Li-doped rutile SnO₂(001) surface. The surface defect formation energy shows that it is easier for Li to be doped at surface Sn sites than bulk Sn sites in SnO₂. Li at surface and sub-surface Sn sites has a magnetic ground state, and the induced magnetic moments are not localized on the Li site, but spread over Sn and O sites. The surface electronic structures show that Li at surface Sn sites shows 100% spin-polarization (half metallic), whereas Li at sub-surface Sn sites does not have a half metallic state due to Li–Sn hybridized orbitals. The spin-polarized surface has a ferromagnetic ground state, therefore, ferromagnetism is expected in the Li-doped SnO₂(001) surface.