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In this paper, the electronic structure and magnetic properties of SnO2 doped with non-metallic elements (N) and transition metal elements (Mo, Ru, Rh, Pd) are calculated and analyzed based on the first principles approach. The results show that: the formation energy is closely related to the transition metal atomic radius, with the increase of the transition metal atomic radius, the formation energy is decreasing, where the N-Mo doping system has the lowest formation energy, so the system is the easiest to doping formation; energy band structure analysis shows that due to the number and distribution of spin up/spin down impurity energy levels of the doping system are asymmetric, the doping systems are magnetic generation; further exploration of the density of states shows that The magnetic properties of the doped system are due to the p-d orbital hybridisation between the transition metal atoms and the N atoms, the vacancies in the outermost electron orbitals and the single electron coupling. The results show that the SnO2 system is magnetic due to the introduction of doping atoms, and the doped system exhibits subferromagnetic properties, with the best magnetic moment of 1.88 μB for the N-Rh doped system, which is expected to be a good dilute magnetic semiconductor material. [ABSTRACT FROM AUTHOR]

The electronic structure, magnetic properties and optical properties of anatase TiO2 and Cr doped anatase TiO2 ( 1/8, 1/16, 1/32) were studied by first principles GGA + U method. The calculation results show that the binding energy of Ti 0. 9375 Cr0. 0625 O2 is the smallest in all doping systems. Therefore, the stability of Ti 0. 9375 Cr0. 0625 O2 system is higher than that of Ti0. 875 Cr0. 125 O2 and Ti0. 96875 Cr0. 03125 O2, the doping of Cr leads to lattice distortion, which is beneficial to the separation of photogenerated holes and electron pairs, and improves the photocatalytic performance. At the same time, because of the interaction of Cr - 3d and 0 - 2p electrons, the doped system presents ferromagnetic properties, and with the increase of doping concentration, the system will have better ferromagnetic properties. Compared with the intrinsic TiO2, the absorption band edge of the doped system is red shifted and the spectral response range is enlarged, Moreover, with the increase of doping concentration, the light response range also increases, which effectively enhances the absorption ability of the system for visible light. [ABSTRACT FROM AUTHOR]