Departamento de Física, ICEx, Universidade Federal de Minas Gerais, 31270-901, Belo Horizonte, MG, Brazil.
Nano Lett. 2012 Oct 10;12(10):5097-102. doi: 10.1021/nl3017434. Epub 2012 Sep 12.
Ab initio calculations indicate that while the electronic states introduced by tilt grain boundaries in graphene are only partially confined to the defect core, a translational grain boundary introduces states near the Fermi level that are very strongly confined to the core of the defect, and display a ferromagnetic instability. The translational boundary lies along a graphene zigzag direction and its magnetic state is akin to that which has been theoretically predicted to occur on zigzag edges of graphene ribbons. Unlike ribbon edges, the translational grain boundary is fully immersed within the bulk of graphene, hence its magnetic state is protected from the contamination and reconstruction effects that have hampered experimental detection of the magnetic ribbon states. Moreover, our calculations suggest that charge transfer between grain boundaries and the bulk in graphene is short ranged, with charge redistribution confined to ~5 Å from the geometric center of the 1D defects.
从头算表明，虽然倾斜晶界在石墨烯中引入的电子态仅部分局限于缺陷核心，但平移晶界在费米能级附近引入的态非常强烈地局限于缺陷的核心，并表现出铁磁不稳定性。平移边界沿石墨烯锯齿方向，其磁态类似于理论上预测的在石墨烯带状锯齿边缘发生的磁态。与带状边缘不同，平移晶界完全沉浸在石墨烯的体相中，因此其磁态不受阻碍实验检测磁带状状态的污染和重构效应的影响。此外，我们的计算表明，石墨烯中晶界与体相之间的电荷转移是短程的，电荷再分布局限于 1D 缺陷几何中心~5Å 以内。
