Zeng Hui, Wu Meng, Wang Hui-Qiong, Zheng Jin-Cheng, Kang Junyong
Fujian Provincial Key Laboratory of Semiconductors and Applications, Collaborative Innovation Center for Optoelectronic Semiconductors and Efficient Devices, Department of Physics, Xiamen University, Xiamen 361005, China.
Department of Physics, Xiamen University Malaysia, Sepang 43900, Selangor, Malaysia.
Materials (Basel). 2020 Dec 12;13(24):5686. doi: 10.3390/ma13245686.
The magnetic and electronic properties of boron-doped SrTiO have been studied by first-principles calculations. We found that the magnetic ground states of B-doped SrTiO strongly depended on the dopant-dopant separation distance. As the dopant-dopant distance varied, the magnetic ground states of B-doped SrTiO can have nonmagnetic, ferromagnetic or antiferromagnetic alignment. The structure with the smallest dopant-dopant separation exhibited the lowest total energy among all configurations considered and was characterized by dimer pairs due to strong attraction. Ferromagnetic coupling was observed to be stronger when the two adjacent B atoms aligned linearly along the B-Ti-B axis, which could be associated with their local bonding structures. Therefore, the symmetry of the local structure made an important contribution to the generation of a magnetic moment. Our study also demonstrated that the O-Ti-O unit was easier than the Ti-B-Ti unit to deform. The electronic properties of boron-doped SrTiO tended to show semiconducting or insulating features when the dopant-dopant distance was less than 5 Å, which changed to metallic properties when the dopant-dopant distance was beyond 5 Å. Our calculated results indicated that it is possible to manipulate the magnetism and band gap via different dopant-dopant separations.
通过第一性原理计算研究了硼掺杂SrTiO的磁性和电子性质。我们发现，硼掺杂SrTiO的磁性基态强烈依赖于掺杂剂-掺杂剂的间距。随着掺杂剂-掺杂剂间距的变化，硼掺杂SrTiO的磁性基态可以呈现非磁性、铁磁性或反铁磁性排列。在所有考虑的构型中，掺杂剂-掺杂剂间距最小的结构具有最低的总能量，并且由于强吸引力而以二聚体对为特征。当两个相邻的B原子沿B-Ti-B轴线性排列时，观察到铁磁耦合更强，这可能与其局部键合结构有关。因此，局部结构的对称性对磁矩的产生做出了重要贡献。我们的研究还表明，O-Ti-O单元比Ti-B-Ti单元更容易变形。当掺杂剂-掺杂剂间距小于5 Å时，硼掺杂SrTiO的电子性质倾向于呈现半导体或绝缘特性，而当掺杂剂-掺杂剂间距超过5 Å时，其电子性质转变为金属特性。我们的计算结果表明，通过不同的掺杂剂-掺杂剂间距可以操纵磁性和带隙。
