Song Y Q, Zhang H W, Yang Q H, Liu Y L, Li Y X, Shah L R, Zhu H, Xiao John Q
State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054, People's Republic of China.
J Phys Condens Matter. 2009 Mar 25;21(12):125504. doi: 10.1088/0953-8984/21/12/125504. Epub 2009 Mar 3.
The electronic structure and magnetic properties of Co-doped CeO(2) are theoretically investigated by first principles calculations based on the density functional theory + U (DFT+U) methods, using the WIEN2k package. With the presence of oxygen vacancies (V(O)) in CeO(2), d and f orbits of Ce are obviously pulled closer to the Fermi level, but without spin polarization. On the other hand, in Co-doped CeO(2), V(O) defects can lead to strong ferromagnetic coupling between the nearest neighboring Co ions. Such ferromagnetic exchange coupling is mainly attributed to spin splitting of Co 3d states, via electrons trapped in V(O). The results provide direct evidence for the F-center mediated exchange interaction in oxide-based magnetic semiconductors.
采用基于密度泛函理论+U（DFT+U）方法的第一性原理计算，使用WIEN2k软件包，对Co掺杂的CeO₂的电子结构和磁性进行了理论研究。在CeO₂中存在氧空位（V(O)）时，Ce的d轨道和f轨道明显向费米能级靠近，但没有自旋极化。另一方面，在Co掺杂的CeO₂中，V(O)缺陷可导致最近邻Co离子之间产生强铁磁耦合。这种铁磁交换耦合主要归因于通过捕获在V(O)中的电子实现的Co 3d态的自旋分裂。这些结果为氧化物基磁性半导体中F中心介导的交换相互作用提供了直接证据。
