Ab initio study on magnetism of SnO2 (110) surface with non-metallic elements doping

Abstract

The electronic structure and magnetic properties of SnO2 (110) surface with anion vacancy and non-metallic elements doping have been studied by using ab initio calculations based on density functional theory (DFT). The perfect SnO2 (110) surface is a non-magnetic semiconductor. The calculated results show that although oxygen vacancy has the lowest formation energy, it cannot introduce local magnetic moment on the surface. For boron (B), carbon (C) and nitrogen (N) doped systems, the formation energy of impurity C is the highest due to sp3 hybridization. The research results show that B, C and N can introduce local magnetic moments on the (110) surface which will cause the system to produce high spin state (S = 1/2 or 1), and the magnetic moments are 1.38 μB, 1.80 μB and 1.00 μB, respectively. Impurity levels appear in the band gap near the Fermi level. Further analysis shows that the magnetic moments are mainly localized near the doped atoms. Studies on magnetic coupling between impurity atoms at different distances reveal that C–C are always coupled ferromagnetically, while N–N are always coupled antiferromagnetically. The energy difference between the antiferromagnetic state and ferromagnetic state is large at each C–C distance in the C-doped system. This indicates that the Curie temperature of the C-doped SnO2 (110) surface is likely to be above room temperature. Our findings are beneficial to the development of spintronics.