Density functional study of magnetic properties in Zn-doped SnO_2

摘要

Magnetic properties in Zn-doped SnO_2 are examined through the first-principles electronic structure calculations based on density functional theory. Our results reveal that Zn-doping induces localized spin magnetic moments primarily on the first coordination shell of O atoms surrounding the Zn atom as well on Zn atom with total magnetic moment of 1.47 μb per supercell. Holes localized on O atoms in ZnO_6 are polarized with the same spin orientation as that of the dopant. Ferromagnetic coupling between Zn ions in Zn-doped SnO_2 is attributed to the hole-mediated p-d exchange coupling interaction. With respect to native defects in Zinc-doped SnO_2, formation of oxygen vacancy (V_o) is suppressed whereas formation of tin vacancy (V_(Sn)) is facilitated due to Zn-doping. It is found that the observed ferromagnetism in Zn-doped SnO_2 mainly originates from the Zn dopant rather than exclusively the formation of V_(Sn).