First-principles study of ferromagnetism in Zn- and Cd-doped SnO2

► Substitutional Zn and Cd introduce holes in the minority-spin 2p orbitals of the O. ► Magnetic moment induced by doping mainly comes from the 2p orbitals of the O. ► U correction for the O-2p states transforms ground states of doped SnO2 to insulating. ► Coupling between the moments induced by two dopants is ferromagnetic.