UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore-452001, India.
J Phys Condens Matter. 2011 Jul 13;23(27):276005. doi: 10.1088/0953-8984/23/27/276005. Epub 2011 Jun 21.
The electronic and magnetic properties of TiO₂, TiO₁.₇₅, TiO₁.₇₅N₀.₂₅, and TiO₁.₇₅F₀.₂₅ compounds have been studied by using ab initio electronic structure calculations. TiO₂ is found to evolve from a wide-band-gap semiconductor to a narrow-band-gap semiconductor to a half-metallic state and finally to a metallic state with oxygen vacancy, N-doping and F-doping, respectively. The present work clearly shows the robust magnetic ground state for N-and F-doped TiO₂. The N-doping gives rise to a magnetic moment of ~ 0.4 μ(B) at the N site and ~ 0.1 μ(B) each at two neighboring O sites, whereas F-doping creates a magnetic moment of ~ 0.3 μ(B) at the nearest Ti atom. Here we also discuss the possible cause of the observed magnetic states in terms of the spatial electronic charge distribution of Ti, N, and F atoms responsible for bond formation.
采用第一性原理电子结构计算研究了 TiO₂、TiO₁.₇₅、TiO₁.₇₅N₀.₂₅和 TiO₁.₇₅F₀.₂₅化合物的电子和磁性质。研究发现，TiO₂ 分别通过氧空位、N 掺杂和 F 掺杂，从宽带隙半导体演变为窄带隙半导体、半金属态，最终变为金属态。本工作清楚地表明，N 和 F 掺杂的 TiO₂具有稳定的磁性基态。N 掺杂在 N 位产生约 0.4 μ(B)的磁矩，在两个相邻的 O 位各产生约 0.1 μ(B)的磁矩，而 F 掺杂在最近的 Ti 原子上产生约 0.3 μ(B)的磁矩。在这里，我们还根据负责成键的 Ti、N 和 F 原子的空间电子电荷分布，讨论了观察到的磁性状态的可能原因。
