State Key Laboratory of Surface Physics, Department of Physics, Fudan University, Shanghai, People's Republic of China.
Nanotechnology. 2010 Sep 24;21(38):385201. doi: 10.1088/0957-4484/21/38/385201. Epub 2010 Aug 26.
Magnetic and spin-polarized transport properties in zigzag-edged graphene nanoflakes were investigated from first-principles calculations. Ferrimagnetic structure was found to be the ground state for triangular shaped graphene flakes. Magnetism is weakened by doping B or N atoms into the flakes, and it is enhanced if F atoms are doped in certain sublattices of the flakes. The magnetic properties can be rationalized by the behaviors of dopants as well as interactions between dopants and the host atoms. A perfect (100%) spin filtering effect was achieved for the pure or B doped graphene flake sandwiched between two gold electrodes. The orientation of the spin current is found to be flipped if the flake is doped with N, O, or F atoms. The orientation-tunable spin filtering effect is potentially useful in practical applications.
基于第一性原理计算，研究了锯齿形边缘石墨烯纳米片中的磁性和自旋极化输运性质。发现三角形石墨烯薄片的基态为反铁磁结构。掺杂 B 或 N 原子会削弱磁性，如果 F 原子掺杂到薄片的某些亚晶格中，磁性会增强。通过掺杂剂的行为以及掺杂剂与主原子之间的相互作用，可以合理地解释磁性性质。对于夹在两个金电极之间的纯或 B 掺杂石墨烯薄片，实现了完美的（100%）自旋过滤效应。如果薄片掺杂 N、O 或 F 原子，自旋电流的方向会发生翻转。这种具有可调取向的自旋过滤效应在实际应用中可能很有用。
