First-principles Calculation On The Doped Rutile TiO₂

The information carrier of traditional electronic components is electronic charge, but the electronic spin is not considered. In recent years, studies on the semiconductor spintronics indicate that the diluted magnetic semiconductors (DMS) can be used to manage and store information by means of the electronic charge and spin. However, nowadays, the key to semiconductor spintronics is that the efficiency of spin-polarized electrons injected into semiconductors is very low, one needs to find some magnetic materials with high spin-polarization. Half-metallic ferromagnet has a higher Curie temperature and almost 100% spin-polarization. Therefore, it will become the perfect spin injection fountain to semiconductor. TiO₂-base diluted magnetic semiconductors have been the studied hotspot for its good stability and magnetic properties.In this paper, our purpose is to study the influence of the doped position of transition metal atoms on the stability and electronic structure of the rutile TiO₂. With the help of the plane-wave pseudopotential (PWPP) method based on the density functional theory (DFT), we investigated the influence of the doped position of transition metal atoms on the stability and electronic structure of the M-doped(M=V or Cr) rutile TiO₂, besides, we discuss the electronic structure and magnetic properties of Mn, Fe and Co delta-doped TiO₂.For Ti6M2O16(M=V,Cr), our computational results indicate that the spin-up (majority spin) electrons are metallic while there is an obvious energy gap around the Fermi level. Moreover, the total magnetic moment of Ti6M2O16 is up to or near a integer, and it has the room temperature ferromagnetism; Because of the John-Teller effect and the p-d hybridization, for the two configurations which doped atoms is closer, their energy is the lowest in the four configurations and approaches each other. The ground state of Mn delta-doped TiO₂ is antiferromagnetic while the ground state of Fe and Co delta-doped TiO₂ is ferromagnetic; Co delta-doped TiO₂ is without the antiferromagnetic state, but the energy difference of the non-magnetic and ferromagnetic states indicates the room temperature ferromagnetism. Fe delta-doped TiO₂ takes on room temperature ferromagnetism, and the eg orbit splits for the John-Teller effect. Co-ions have high orbital moment, so the moment of the Co atom is lower than the imagined in the TiO₂ crystal cell.