Carbon induced magnetism of SnO2 surfaces

•We investigate surface magnetism in (110), (001) and (101) surfaces of SnO2:C.•(110) surface provides the main contribution to the surface magnetism of SnO2:C.•Magnetism predominantly come from C-2p orbitals and crystal field transformation.

The magnetism induced by Carbon (C) in SnO2 surfaces are investigated by first principle calculations. The results show that C substitution at the outmost surface oxygen sites can induce magnetism in (110), (001) and (101) surfaces of SnO2. (110) surface is the most stable surface and the magnetism in which is stronger than that in other two surfaces, indicating that it is (110), but not other surfaces provides the main contribution to the surface magnetism of C-doped SnO2 (SnO2:C). The magnetic moments predominantly come from C-2p orbitals, which arise from the crystal field transformation induced by the loss of coordinated atoms and the destroy of the local symmetry, and is enhanced by the local lattice distortion due to the Jahn–Teller effect. In all three surface slabs, the magnetism decays when C dopants are deeper from the outmost surfaces and disappears eventually. This work provides more rational understanding to the observed magnetism in SnO2:C materials than ever.

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