Sun Qiang, Yao Xuelin, Gröning Oliver, Eimre Kristjan, Pignedoli Carlo A, Müllen Klaus, Narita Akimitsu, Fasel Roman, Ruffieux Pascal
Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany.
Nano Lett. 2020 Sep 9;20(9):6429-6436. doi: 10.1021/acs.nanolett.0c02077. Epub 2020 Aug 7.
Exact positioning of sublattice imbalanced nanostructures in graphene nanomaterials offers a route to control interactions between induced local magnetic moments and to obtain graphene nanomaterials with magnetically nontrivial ground states. Here, we show that such sublattice imbalanced nanostructures can be incorporated along a large band gap armchair graphene nanoribbon on the basis of asymmetric zigzag edge extensions, achieved by incorporating specifically designed precursor monomers. Scanning tunneling spectroscopy of an isolated and electronically decoupled zigzag edge extension reveals Hubbard-split states in accordance with theoretical predictions. Mean-field Hubbard-based modeling of pairs of such zigzag edge extensions reveals ferromagnetic, antiferromagnetic, or quenching of the magnetic interactions depending on the relative alignment of the asymmetric edge extensions. Moreover, a ferromagnetic spin chain is demonstrated for a periodic pattern of zigzag edge extensions along the nanoribbon axis. This work opens a route toward the fabrication of graphene nanoribbon-based spin chains with complex magnetic ground states.
在石墨烯纳米材料中精确排列亚晶格失衡的纳米结构，为控制诱导局部磁矩之间的相互作用以及获得具有非平凡磁基态的石墨烯纳米材料提供了一条途径。在此，我们表明，基于不对称锯齿形边缘延伸，可以沿着大带隙扶手椅型石墨烯纳米带引入这种亚晶格失衡的纳米结构，这是通过引入专门设计的前驱体单体实现的。对一个孤立且电解耦的锯齿形边缘延伸进行扫描隧道光谱分析，发现了与理论预测相符的哈伯德分裂态。基于平均场哈伯德模型对成对的这种锯齿形边缘延伸进行建模，结果表明，根据不对称边缘延伸的相对排列方式，磁相互作用会呈现铁磁性、反铁磁性或淬灭。此外，对于沿纳米带轴的锯齿形边缘延伸的周期性图案，展示了一个铁磁自旋链。这项工作为制造具有复杂磁基态的基于石墨烯纳米带的自旋链开辟了一条道路。
